Systems, devices, materials, and methods for atmospheric water extraction using vibrational and / or acoustic actuation

Abstract

A system for atmospheric water extraction is provided. The system can include an actuator configured to produce at least one of mechanical vibrations or acoustical vibrations, an electrical circuit in electrical communication with the actuator device and configured to drive the actuator with one or more of pre-designed frequencies, amplitudes, or duty cycle, and a moisture-harvesting material disposed in contact with the actuator. The system can enable energy-efficient extraction of water from atmospheric moisture through vibrational and acoustic actuation mechanisms that operate without relying primarily on thermal evaporation processes. The actuator can generate vibrational energy across frequency ranges from infrasound to ultrasonic frequencies to disrupt water-sorbent interactions and facilitate moisture release from the moisture-harvesting material.

Description

Attorney Docket No. MIT 25345 PCT | 88212-427691SYSTEMS, DEVICES, MATERIALS, AND METHODS FOR ATMOSPHERIC WATER EXTRACTION USING VIBRATIONAL AND / OR ACOUSTIC ACTUATIONCROSS REFERENCE TO RELATED APPLICATION(S)

[0001] The present disclosure claims priority to and the benefit of U.S. Provisional Application No. 63 / 718,554. entitled "Method, Apparatus, and Materials for Atmospheric Moisture Extraction By Vibrational and / or Acoustic Actuation," filed on November 8, 2024, and U.S. Provisional Application No. 63 / 801,113, entitled "Methods and Apparatus for Moisture Extraction from Super Absorbent Materials by Vibrational Actuation," filed on May 6, 2025, the contents of each which is incorporated by reference herein in its entirety.FIELD

[0002] The present disclosure relates to systems, devices, materials, and methods for atmospheric water extraction, and more particularly relates to systems, devices, materials, and methods for extracting moisture from atmospheric water harvesting sorbents and other super absorbent materials using vibrational and / or acoustic actuation to achieve energyefficient water production.BACKGROUND

[0003] Atmospheric water harvesting (AWH) technology represents an emerging approach to water production that extracts moisture directly from ambient air to generate clean water. This technology offers potential for decentralized water production, particularly in regions where conventional water sources are limited or where large-scale water infrastructure is impractical. The atmosphere contains approximately 12,900 billion tons of fresh water in vapor form, representing a vast and ubiquitous resource that exists at virtually any geographical location on Earth. AWH systems typically operate through one of two primary mechanisms: active refrigeration technology that cools air below the dew point to promote condensation, or sorption-desorption technology that employs porous hydrophilic materials to capture moisture from air followed by water extraction processes.

[0004] Active refrigeration systems face challenges in scaling down to economically viable decentralized applications, while sorption-desorption systems in their current state exhibit high energy consumption due to the energy-intensive nature of water desorption from AWH materials. Conventional desiccants such as silica gel, zeolite, and activated aluminaAttorney Docket No. MIT 25345 PCT | 88212-427691 may require temperatures as high as 160°C to release captured water. More recently developed sorbents including hydrogels, metal-organic frameworks (MOFs), and various saltbased systems operate at lower but still moderately high temperatures in the 60°C to 80°C range, making water release an energy-intensive process. Current AWH prototypes demonstrate energy consumption that exceeds predicted thermal limits by at least an order of magnitude, representing a bottleneck in the practical implementation of sorption-desorption AWH technology.

[0005] The energy efficiency challenges in existing AWH systems stem largely from their reliance on thermal processes for moisture extraction. Heat-driven evaporation processes are fundamentally limited by thermodynamic constraints and require substantial energy input to achieve phase change from liquid to vapor. Additionally, thermal systems often suffer from heat losses to the environment and the energy costs associated with heating both the water and the sorbent materials themselves. These inefficiencies become particularly pronounced in applications where frequent cycling between adsorption and desoiption phases is required to maintain continuous water production.

[0006] Accordingly, there is a need for AWH systems and methods that can extract moisture from the atmosphere with improved energy efficiency and reduced reliance on thermal processes. Such systems would benefit from alternative extraction mechanisms that can operate at lower energy requirements while maintaining effective water production rates across various environmental conditions.SUMMARY

[0007] The presently disclosed embodiments generally relate to systems, devices, materials, and methods for atmospheric water extraction using vibrational and acoustic actuation mechanisms. These systems can enable energy-efficient extraction of moisture from ambient air through non-thermal processes that achieve superior performance compared to conventional heating-based extraction methods. The disclosed technology can utilize mechanical vibrations and acoustic energy to disrupt water-sorbent interactions and facilitate moisture release from atmospheric water harvesting materials without relying primarily on thermal evaporation-condensation processes.

[0008] The vibrational and acoustic actuation approach can achieve energy efficiency improvements of approximately forty -five -fold compared to conventional thermal extraction methods while maintaining comparable or superior moisture extraction rates. The systemsAttorney Docket No. MIT 25345 PCT | 88212-427691 operate across frequency ranges from infrasound to ultrasonic frequencies to optimize extraction performance for different sorbent materials and environmental conditions. The disclosed methods and apparatuses overcome the thermodynamic limitations that constrain conventional thermal desorption processes, offering potential for further efficiency improvements beyond current demonstrations while enabling practical deployment of atmospheric water harvesting technology in arid regions where traditional water sources are limited.

[0009] In one aspect, embodiments relate to a system for atmospheric water extraction. The system includes an actuator configured to produce at least one of mechanical vibrations, acoustical vibrations, magnetic stimuli, or electromagnetic stimuli. An electrical circuit is in electrical communication with the actuator and is configured to drive the actuator with one or more of pre-designed frequencies, amplitudes, or duty cycle. A moisture-harvesting material is disposed in contact with the actuator.

[0010] One or more of the following features can be included. The system can further include at least one of a mesh or a membrane, where the at least one of a mesh or a membrane has zero or multiple perforations or nozzles. The at least one of a mesh or a membrane can be configured to operate as an electrode for at least one of the actuator or the electrical circuit. The system can further include a scaffold integrated within the moistureharvesting material, where the scaffold can be configured to serve as a transducer of vibrational modes. The scaffold can include at least one of a 3D printed structure, a wire grid, a plurality of nano- or micro-particles, a knitted or woven textile, a non-woven structure, or a plurality of fibers, yams, braids, or rods.

[0011] The system can further include an in-situ sensor configured to monitor transient changes in properties of the moisture-harvesting material and provide feedback to at least one of the actuator or the electrical circuit in view of the monitored transient changes in properties. The system can further include a droplet collector to guide water extracted by the actuator. The system can further include an enclosure to collect water extracted by the actuator. In some embodiments, a mechanical support structure to which the actuator is configured to mount or into which the actuator is integrated can be included.

[0012] The actuator can include at least one of piezoelectric films, piezoelectric scaffolds, a piezoelectric element, or fiber-based scaffolds. T he piezoelectric element can include at least one of inorganic piezoelectric materials, including but not limited toAttorney Docket No. MIT 25345 PCT | 88212-427691 lead zirconate titanate (PZT), barium titanate, zinc oxide, or lithium niobate. The piezoelectric films or fiber-based scaffolds can include polymer piezoelectric materials, including but not limited to poly vinylidene fluoride (PVDF), polyvinylidene fluoridetrifluoroethylene (PVDF-TrFE) copolymer, poly-l-lactic acid (PLLA), polyacrylonitrile (PAN), nylon, or silk. The piezoelectric scaffold can include at least one of polymer materials with inorganic micro- or nano-scale fillers or without inorganic micro- or nano-scale fillers.

[0013] The moisture-harvesting material can include one or more of a hydrogel with inorganic micro- or nano-scale fillers or without inorganic micro- or nano-scale fillers, a metal organic framework (MOF), a hygroscopic fibrous material with or without embedded MOF inclusions, a polymer matrix with or without pores, or a hydroscopic salt. The actuator can include one or more of an acoustic speaker, an ultrasonic actuator, a microwave source, or an electromagnetic wave antenna. The electrical circuit can include at least one of: an electric input signal waveform, a mechanism to adjust the driving frequency, or a method to boost or amplify the input voltage through the use of at least one of a booster, a transformer, or an amplifier.

[0014] The actuator can be configured to dynamically monitor the moisture-harvesting material and provide feedback to the electrical circuit. The system can further include one or more additional sensors configured to dynamically monitor a moisture content of the moisture-harvesting material and provide feedback to at least one of the actuator or the electrical circuit in view of the same. The moisture -harvesting material can be configured to have at least one of a high water uptake capacity, fast vapor capture kinetics, or mechanical stability to withstand an actuation-driven water extraction process performed by the actuator.

[0015] The moisture-harvesting material can include a cross-linked hydrogel material. The cross-linked hydrogel material can include at least one of polyacrylamide, alginate (alginic acid, sodium alginate, potassium alginate, ammonium alginate, calcium alginate, propylene glycol alginate, chemically modified alginate, and combinations thereof), polyacrylic acid, hydroxypropyl cellulose, or Poly(N-isopropylacrylamide). The cross-linked hydrogel material can include one, none, or a plurality of lithium chloride, calcium chloride, or magnesium chloride.

[0016] The moisture-harvesting material can be configured to serve as at least one of a vibrational signal resonator or amplifier. The moisture-harvesting material can encapsulate aAttorney Docket No. MIT 25345 PCT | 88212-427691 scaffold that provides mechanical stability and serves as a transducer for vibrational modes propagation through a volume of the moisture-harvesting material. The moisture-harvesting material can encapsulate an active scaffold that is configured to serve as the actuator, or as an additional actuator. The active scaffold can include at least one of a knitted or woven textile, a non-woven structure, or a plurality of fibers, yarns, braids, films, bars, or rods.

[0017] In another aspect, embodiments relate to a method of extracting moisture from an atmosphere. The method includes applying at least one non-thermal stimulus to a moistureharvesting material to extract moisture from the moisture-harvesting material, where the moisture harvesting material has captured the moisture from the atmosphere.

[0018] One or more of the following features can be included. The non-thermal stimulus can include one or more of a mechanical vibration, an acoustical vibration, a microwave stimulus, or a magnetic stimulus. Applying at least one non-thermal stimulus to the moisture-harvesting material can further include driving the applying action by way of an electrical circuit using at least one of pre-designed frequencies, amplitudes, or duty cycles. The moisture -harvesting material can be disposed in contact with an actuator that applies the at least one non-thermal stimulus.

[0019] The method can further include monitoring transient changes in the moistureharvesting material using one or more sensors and providing feedback to at least one of the actuator or an electrical circuit in electrical communication with the actuator, where the electrical circuit drives the actuator. Monitoring transient changes in the moisture-harvesting material can be performed by the actuator. The moisture-harvesting material can operate as at least one of a vibrational signal resonator or an actuator. The moisture-harvesting material can encapsulate an active scaffold and perform the action of applying at least one of a mechanical vibration or an acoustical vibration to an atmosphere to extract moisture from the atmosphere. The method can include operating a mechanical scaffold as a transducer to supply the mechanical vibration. The method can further include guiding the extracted moisture. The method can further include collecting the extracted moisture.BRIEF DESCRIPTION OF DRAWINGS

[0020] This disclosure will be more fully understood from the following detailed description taken in conjunction with the accompanying drawings, in which:Attorney Docket No. MIT 25345 PCT | 88212-427691

[0021] FIG. 1 is a schematic illustration of prior art water extraction from an atmospheric water harvesting sorbent via a heating -induced evaporation-condensation process;

[0022] FIG. 2A is a schematic exploded view of a device for atmospheric water extraction utilizing vibrational actuation;

[0023] FIG. 2B is a schematic illustration of the device of FIG. 2A for atmospheric water extraction utilizing vibrational actuation in which the components are assembled;

[0024] FIG. 3A is an exploded perspective view of a moisture-harvesting device of the present embodiments;

[0025] FIG. 3B is a perspective view of a system that include two assembled devices of FIG. 3A connected to respective electronic circuits during moisture collection;

[0026] FIG. 3C is a graph showing energy efficiency of water extraction of the device of the present embodiments as compared to the prior art;

[0027] FIG. 4A is a front view of a piezoelectric-ceramic-based single-head ultrasonic actuator of the present embodiments;

[0028] FIG. 4B is an exploded view of the actuator of FIG. 4A;

[0029] FIG. 4C is a magnified top view of a membrane with nozzles that is used with the actuator of FIG. 4A;

[0030] FIG. 5A is a perspective view of a moisture-harvesting material used in the methods of the present embodiments;

[0031] FIG. 5B is an exploded view of the assembly of the actuator of FIG. 4A;

[0032] FIG. 5C is a perspective view of the assembled actuator of FIG. 5B;

[0033] FIG. 5D is a perspective view of the moisture -harvesting material of FIG. 5A disposed on the actuator of FIG. 5C;

[0034] FIG. 5E is a magnified perspective view of the assembly of FIG. 5D exposed to high frequency pressure waves for ultrasound stimulation;

[0035] FIG. 5F is a perspective view of the assembly of FIG. 5E;

[0036] FIGS. 6A is a perspective view of a ID piezo array geometry used for water extraction using the system architectures of the present disclosure;Attorney Docket No. MIT 25345 PCT | 88212-427691

[0037] FIG. 6B is a perspective view of a 1.5D piezo array geometry used for water extraction using the system architectures of the present disclosure;

[0038] FIG. 6C is a perspective view of a 2D matrix piezo array geometry used for water extraction using the system architectures of the present disclosure;

[0039] FIG. 6D is a perspective view of an annular array geometry used for water extraction using the system architectures of the present disclosure;

[0040] FIG. 6E is a perspective view of a circular phased array geometry used for water extraction using the system architectures of the present disclosure;

[0041] FIG. 6F is a perspective view of a 2D segmented annular array geometry used for water extraction using the system architectures of the present disclosure;

[0042] FIG. 7A is a schematic representation of an actuator-mesh assembly operating under alternating voltage;

[0043] FIG. 7B is a perspective view of a speaker that exemplifies the actuator-mesh assembly of FIG. 7 A;

[0044] FIG. 7C is a perspective view of an embodiment of an actuator having cage-like structures that is disposed around the moisture harvesting material;

[0045] FIG. 8 is a schematic illustration of a process for engineering and integrating a nano / micro-architectured scaffold within a sorbent material;

[0046] FIGS. 9 A is a schematic illustrations of architectured sorbent configurations with piezoelectric materials of various geometries;

[0047] FIGS. 9B is a schematic illustrations of architectured sorbent configurations with piezoelectric materials of various geometries;

[0048] FIGS. 9C is a schematic illustrations of architectured sorbent configurations with piezoelectric materials of various geometries;

[0049] FIGS. 9D is a schematic illustrations of architectured sorbent configurations with piezoelectric materials of various geometries;

[0050] FIG. 10A is a schematic view of a fabrication of a moisture-harvesting material 116 via electrospinning to create nanofibrous structures;Attorney Docket No. MIT 25345 PCT | 88212-427691

[0051] FIG. 10B is a schematic view of an electrospun nanofiber moisture-harvesting material doped with metal-organic frameworks (MOFs) in a non-woven sheet;

[0052] FIG. 11 is a graph illustrating measured rates of water extraction under piezo actuation of the present embodiments versus conventional Joule heating at the same steadystate temperature;

[0053] FIG. 12A is a graph illustrating results of testing acoustic actuation of microparticle-doped polyacrylamide and lithium chloride (PAM-LiCl) hydrogels at audible frequencies compared to conventional thermal methods across a broad range of operating conditions; and

[0054] FIG. 12B is a graph illustrating water extraction performance from hydrogel materials across musical compositions that incorporate different frequencies.DETAILED DESCRIPTION

[0055] Certain embodiments will now be described to provide an overall understanding of the principles of the structure, function, manufacture, and use of the systems, devices, related components (e.g., actuators, moisture-harvesting materials, sorbents, piezoelectric elements, porous membranes, droplet collectors, scaffolds, electrical circuits, enclosures, and mechanical support structures), and methods disclosed herein. One or more examples of these embodiments are illustrated in the accompanying drawings. Those skilled in the art will understand that the devices and methods specifically described herein and illustrated in the accompanying drawings are non-limiting exemplary embodiments and that the scope of the present disclosure is defined solely by the claims. The features illustrated or described in connection with one exemplary embodiment may be combined with the features of other embodiments. Such modifications and variations are intended to be included within the scope of the present disclosure. Further, to the extent features, components, layers, elements, steps, or the like are described as being "first," "second," "third," etc., and / or "upper," "lower," "top," "bottom," etc., such numerical and / or location ordering / identification is generally arbitrary, and thus such numbering can be interchangeable unless indicated or otherwise understood by those skilled in the art to not be interchangeable. While terms like "proximal" and "distal" as used herein, they are primarily used as a point of reference for describing two portions or ends of an instrument, tool, component, device, system, location in a body, etc. Accordingly, no meaning should be attributed to a specific location with respect to "proximal" or "distal" beyond distinguishing one side from another unless explicitlyAttorney Docket No. MIT 25345 PCT | 88212-427691 indicated. For example, what is referred to herein as a proximal portion or end may be considered distal in operation, and thus, likewise, what is referred to herein as a distal portion or end may be considered proximal in operation.

[0056] The figures provided herein are not necessarily to scale, although a person skilled in the art will recognize instances where the figures are to scale and / or what a typical size is when the drawings are not to scale. Further, to the extent that linear or circular dimensions or shapes are used or described herein, such dimensions are not intended to limit the types of shapes or sizes of such devices, components, etc. A person skilled in the art will recognize that an equivalent to such linear and / or circular dimensions or shapes can be easily determined for any geometric shape (e.g., references to widths and diameters being easily adaptable for circular and linear dimensions, respectively, by a person skilled in the art). While in some embodiments movement of one component is described with respect to another, a person skilled in the art will recognize that other movements are possible. Further, to the extent arrows are used to describe a direction a component can expand or move, these arrows are illustrative and in no way limit the direction the respective component can expand or move. A person skilled in the art will recognize other ways and directions for creating the desired tension or movement.

[0057] Still further, in the present disclosure, like-numbered components of various embodiments generally have similar features when those components are of a similar nature and / or serve a similar purpose, unless otherwise noted or otherwise understood by a person skilled in the art. To the extent the present disclosure includes prototypes, mock-ups, bench models, or the like, a person skilled in the art will recognize how to rely upon the present disclosure to integrate the techniques, systems, devices, and methods into a product, such as atmospheric water harvesting devices, dehumidification systems, industrial drying equipment, and portable water production units. A number of terms may be used throughout the disclosure interchangeably but will be understood by a person skilled in the art. By way of non-limiting example, the terms "actuator," "transducer," "piezoelectric element," "vibrational actuator," and "acoustic actuator" may be used interchangeably with one another. Moreover, it will be appreciated that although features may be discussed with respect to one embodiment within the present disclosure, these features can be applied to every embodiment of the present disclosure where such feature would be supported.

[0058] To the extent terms like "approximately," "about," and "substantially" are used herein, a person skilled in the art will appreciate the scope those words convey in the contextAttorney Docket No. MIT 25345 PCT | 88212-427691 of their usage. In the context of atmospheric water extraction systems, obtaining a certain degree of frequency precision, energy efficiency measurements, moisture extraction rates, and / or vibrational amplitude alignment, among other operational parameters and the like may be difficult, and thus use of terms like "approximately," "about," and "substantially" is intended to address this difficulty. A person skilled in the art will understand what constitutes how close a particular dimension or operational parameter should be to still fall within the spirit of the quantification and description provided for herein. Even in instances where such terminology is not used, and a dimension or operational parameter just includes the number or term (e.g., "parallel" is used instead of "substantially parallel"), a person skilled in the art will appreciate that, unless explicitly indicated otherwise, temis like "approximately," "about," and "substantially" are applicable to those dimensions and temis as well. The foregoing notwithstanding, a person skilled in the art will appreciate that terms like "approximately," "about," and "substantially" at least encompass frequencies, energy consumption values, extraction rates, dimensions, quantities, etc. that are ±10%, 10°, etc. of the provided amount, or encompass dimensions that are ±5%, 5°, etc. of the provided amount, unless indicated otherwise or otherwise known to those skilled in the art. The present disclosure appreciates that a person skilled in the art, in view of the present disclosure, understands suitable placements for various features of the disclosed systems, devices, actuators, and sorbent materials, and related components of any of the same, and thus to the extent a particular operational parameter, frequency, or dimensional specification is described, unless it is explicitly indicated that such parameter is critical, a person skilled in the art will appreciate other operational parameters, frequencies, or dimensions that are possible without impacting the overall system or device performance.

[0059] Atmospheric water harvesting (AWH) technology represents a promising approach for extracting moisture from ambient air to generate fresh water, particularly in arid regions where traditional water sources may be limited. Conventional AWH systems typically rely on sorption-desorption processes that employ porous hydrophilic sorbents with high adsorption capacity to collect moisture from air, followed by water extraction via heating-induced evaporation-condensation processes. However, these thermal extraction methods exhibit prohibitively high energy consumption due to the high heat of water desorption from AWH materials, with desorption temperatures ranging from 60°C to 300°C depending on the sorbent material used. The energy efficiency of conventional thermal extraction systems typically operates at least an order of magnitude higher than predictedAttorney Docket No. MIT 25345 PCT | 88212-427691 thermal limits, representing a major bottleneck for practical deployment of sorptiondesorption AWH technology.

[0060] The present disclosure addresses these limitations through a novel approach that utilizes vibrational and / or acoustic actuation for moisture extraction without relying primarily on thermal evaporation. That is, the present disclosure generally relates to systems, devices, materials, and methods for using vibrational and / or acoustic actuation to extract moisture from an environment (e.g., atmosphere) — the devices being referred to as actuators e.g., vibrational actuators, acoustic actuators, vibrational and acoustic actuators). In some instances such devices and systems may fully vibrational, in other instances such devices and systems may be fully acoustic, in still other instances such devices and systems may include both vibrational and acoustic capabilities. For the purposes of the present disclosure, actuators can encompass any device that is capable of vibrating.

[0061] The use of vibrational and / or acoustic actuation can be used in lieu of heat or in conjunction with heat. To the extent heat is used as part of extraction, the present devices and systems are not reliant on heat to do the extraction. This breakthrough enables significantly improved energy efficiency compared to state-of-the-art systems by extracting water from sorbent materials through mechanical processes rather than energy-intensive heating cycles. With heat as a complementary piece, it can still prove useful, but the ability to reduce or eliminate use of heat can prove beneficial, as it allows for various drawback in using heat to be avoided. The vibrational actuation approach can achieve energy efficiency improvements of approximately forty -five -fold compared to conventional thermal extraction methods, while maintaining comparable or superior moisture extraction rates. The disclosed systems and methods are not bound by the thermal limits that constrain conventional thermal desorption processes, offering potential for further efficiency improvements beyond current demonstrations. Further, the present disclosure also implements various monitoring capabilities to assist in improving performance, such as achieving greater efficiency. Monitoring can be provided in an electrical circuit, which in at least some instances, can use one or more sensors to help control when the system should start and stop to achieve peek (or at least desired) efficiency.

[0062] It will be appreciated that while vibrational and acoustic actuation is largely discussed herein, alternative non-thermal stimuli for moisture extraction, which may include various forms of mechanical and electromagnetic actuation beyond conventional vibrationalAttorney Docket No. MIT 25345 PCT | 88212-427691 approaches, also fall within the scope of the present disclosure. For example, the system may operate using electromagnetic or magnetic field stimuli in addition to or instead of mechanical and acoustical vibrations for moisture extraction from sorbent materials. Magnetic field actuation can induce changes in sorbent properties or create forces that facilitate water release from hygroscopic materials through electromagnetic interactions, such as via electromagnetic antennae. The system may also operate using microwave radiation as a stimulus for moisture extraction from sorbents, where microwave energy can selectively heat water molecules within the sorbent matrix while minimizing energy losses to the surrounding material structure.

[0063] Light or photon absorption may serve as an additional stimulus for moisture extraction, including utilization of the photomolecular effect for rapid moisture extraction from sorbent materials. The photomolecular effect can facilitate water molecule cluster evaporation through interaction with transverse-polarized visible light, providing an alternative pathway for moisture release that does not require conventional thermal heating. The system may further operate using strain as a mechanical stimulus for moisture extraction from sorbents, where mechanical deformation of the sorbent structure can induce configurational changes in polymer networks and modify particle diffusion processes to promote water release. Electrochemical processes may also serve as a stimulus for moisture extraction from sorbents, where electrical fields or electrochemical reactions can alter the binding affinity between water molecules and sorbent surfaces to facilitate moisture extraction.

[0064] Referring to FIG. 1 , conventional atmospheric water harvesting systems employ thermal extraction methods that rely on heating-induced evaporation-condensation processes to extract moisture from sorbent materials. FIG. 1 illustrates a prior art approach where an AWH sorbent 100 with high adsorption capacity is used to capture water vapor 101 from the ambient atmosphere. The sorbent 100 stores water within its volume through physical and chemical adsorption mechanisms, resulting in material swelling as moisture accumulates within the sorbent structure. The water vapor 101 becomes bound to hydrophilic surface groups on the sorbent material through van der Waals forces and stronger dipole-ion interactions, with water molecules forming hydrogen bonds among themselves and with hydrophilic groups such as hydroxyl (-OH), carboxyl (-COOH), amino (-NFL), and other polar functional groups present on the sorbent surface.Attorney Docket No. MIT 25345 PCT | 88212-427691

[0065] To release the captured moisture from the sorbent 100, the conventional thermal extraction process requires heating the sorbent to an elevated temperature, which promotes water evaporation inside a condenser enclosure 102. The heating process provides thermal energy to overcome the binding forces between water molecules and the sorbent material, causing the adsorbed water to transition from liquid or bound states to vapor form. The water vapor generated through thermal heating is then condensed within the enclosure 102, allowing for collection of liquid water through conventional condensation mechanisms. This thermal desorption process typically requires temperatures approximately ranging from about 60°C to about 300°C depending on the specific sorbent material used, with conventional desiccants such as silica gel, zeolite, and activated alumina requiring the highest desorption temperatures.

[0066] The energy efficiency of thermal water extraction systems is fundamentally limited by the thermodynamic properties of water phase transitions. The thermal limit for moisture extraction is defined by the enthalpy of water vaporization, which represents the minimum energy required to convert liquid water to vapor at a given temperature. At 100°C, the enthalpy of vaporization for water is approximately 2.26 MJ / kg, establishing a theoretical lower bound for energy consumption in thermal extraction processes. However, practical thermal extraction systems operate with energy efficiencies that are at least an order of magnitude higher than this thermal limit due to heat losses, sensible heating requirements for the sorbent material, and inefficiencies in the heating and condensation processes.

[0067] The energy intensity of conventional thermal desorption-condensation systems can be expressed as the ratio of the enthalpy of water vaporization to the thermal efficiency of the extraction process. Real thermal extraction systems exhibit thermal efficiencies of approximately 0. 1 or less, resulting in energy consumption values that significantly exceed the theoretical minimum. This poor energy efficiency represents a major bottleneck for the practical deployment of sorption-based AWH technology, particularly in applications where energy resources are limited or where economic viability depends on minimizing operational costs. The high energy requirements of thermal extraction methods also limit the feasibility of using renewable energy sources such as solar power for autonomous AWH system operation, as the energy input requirements often exceed what can be practically supplied through distributed renewable energy systems.

[0068] Referring to FIGS. 2A-2B, the present disclosure provides a system 10 for atmospheric water extraction that can utilize vibrational actuation to overcome the limitationsAttorney Docket No. MIT 25345 PCT | 88212-427691 of conventional thermal extraction methods. FIGS. 2A and 2B illustrate the general schematic concept of the new extraction method and apparatus, which represents a fundamental departure from heating-induced evaporation-condensation processes. The system 100 can employ mechanical vibrations to extract moisture from sorbent materials through non-thermal mechanisms, enabling significantly improved energy efficiency compared to conventional thermal approaches.

[0069] The system 110 can include an actuator 112 configured to produce at least one of mechanical vibrations or acoustical vibrations for moisture extraction from atmospheric water harvesting materials. The actuator 112 can generate vibrational energy across a range of frequencies, from audible sound frequencies in the range of about 16 Hz to about 20 kHz up to ultrasonic frequencies extending from about 20 kHz to about 250 MHz or higher. The actuator 112 can include piezoelectric elements that leverage the indirect piezoelectric effect in non-centrosymmetric crystals and ceramics to convert electrical power into mechanical stress and vibrational waves. The vibrational energy generated by the actuator 1 12 can create alternating compression and rarefaction cycles that disrupt hydrogen bonds between water molecules and sorbent surfaces, facilitating moisture release through mechanical rather than thermal mechanisms.

[0070] An electrical circuit 114, as also shown in FIG. 4B, can be provided in electrical communication with the actuator 112. The electrical circuit 114 can be configured to drive the actuator 1 12 with one or more of pre-designed frequencies, amplitudes, or duty cycles. The electrical circuit 114 can include at least one of an electric input signal waveform, a mechanism to adjust the driving frequency, or a method to boost or amplify the input voltage through the use of at least one of a booster, a transformer, or an amplifier. The electrical circuit 114 can generate input signals with tunable alternating waveforms, allowing for precise control of the vibrational characteristics applied to the moisture -harvesting material. The circuit 114 can transmit signals intermittently or continuously, with adjustable duty cycles that can optimize energy efficiency while maintaining effective moisture extraction rates. The frequency adjustment mechanism can enable the system 110 to operate at resonant frequencies that maximize vibrational energy transfer to the sorbent material, while voltage amplification components ensure sufficient power delivery to achieve effective actuation.

[0071] A moisture -harvesting material 116 can be disposed in contact with the actuator112 to facilitate moisture extraction through vibrational actuation. The moisture-harvestingAttorney Docket No. MIT 25345 PCT | 88212-427691 material 116 can include various types of sorbents including hydrogels, metal-organic frameworks (MOFs), hygroscopic salts, activated carbon, silica gels, zeolites, combinations thereof, or other porous hydrophilic materials with high water adsorption capacity. The moisture-harvesting material 116 can capture water vapor from the ambient atmosphere through physical and chemical adsorption mechanisms, storing the captured moisture within its structure until extraction is initiated through vibrational actuation. The contact between the moisture-harvesting material 116 and the actuator 112 can enable efficient transfer of vibrational energy into the sorbent volume, creating mechanical forces that promote water release without requiring thermal heating.

[0072] As further shown in FIGS. 2 A and 2B, the system 110 may optionally include at least one of a mesh or a membrane 118, where the at least one of a mesh or a membrane 118, which can have zero or multiple perforations or nozzles (not shown) formed therein. That is, while in some embodiments, there is direct contact between the moisture-harvesting material 1 16 and the actuator 112, in some embodiments, the membrane 1 18 can be positioned between the actuator 112 and the moisture-harvesting material 116, or integrated within the actuator 112 assembly to facilitate moisture extraction and collection. The perforations or nozzles in the membrane 118 can allow for extracted water to pass through while providing structural support for the moisture-harvesting material 116 during vibrational actuation. In some embodiments, the membrane 118 can be configured to operate as an electrode for at least one of the actuator 112 or the electrical circuit 114. When functioning as an electrode, the membrane 118 can serve dual purposes by providing electrical connectivity for operation of the actuator 112 while simultaneously facilitating water extraction and collection processes.

[0073] In some embodiments, the membrane 118 can serve as a transducer for vibrational modes, enabling efficient transmission of mechanical energy from the actuator 112 to the moisture -harvesting material 116. The porous structure of the membrane 118 can allow vibrational waves to propagate through the material 116 while maintaining structural integrity during actuation cycles. The transducer function of the membrane 118 can enhance the distribution of vibrational energy throughout the sorbent volume, improving extraction efficiency by ensuring that mechanical forces reach water molecules bound in different regions of the moisture-harvesting material 116. The membrane 118 can be fabricated from materials with suitable acoustic properties to minimize energy losses duringAttorney Docket No. MIT 25345 PCT | 88212-427691 vibrational transmission while providing adequate mechanical strength to withstand repeated actuation cycles.

[0074] As shown, the system 110 can, optionally, include a scaffold 120, e.g., a mechanical scaffold, integrated within the moisture -harvesting material 116 that can be configured to serve as a transducer of vibrational modes. The scaffold 1 0 can be distributed throughout the volume of the moisture -harvesting material 116 to enhance the propagation of vibrational energy from the actuator to regions within the sorbent that may otherwise be difficult to reach through surface actuation alone. The scaffold structure 120 can facilitate uniform distribution of mechanical forces throughout the sorbent volume, ensuring that water molecules bound in interior regions of the moisture-harvesting material experience sufficient vibrational energy to promote release. The scaffold 120 can include various architectured structures including embedded nano- or micro-particles, 3D printed frameworks, wire grids, knitted or woven textiles, non-woven structures, or pluralities of fibers, yarns, braids, or rods that can provide both mechanical support and vibrational transmission capabilities.

[0075] The scaffold 120 can be engineered to have specific resonant frequencies that match or complement the operating frequencies of the actuator 112, thereby enabling enhanced vibrational coupling between the actuator 112 and the moisture-harvesting material 116. The scaffold structure 120 may be designed with controlled porosity and surface area characteristics that promote efficient moisture capture during adsorption while facilitating rapid water release during vibrational extraction. The integration of the scaffold 120 within the moisture-harvesting material 116 can also provide structural stability that prevents sorbent degradation during repeated actuation cycles, extending the operational lifetime of the atmospheric water harvesting system.

[0076] In some embodiments, the system 110 can optionally include a droplet collector 122 to guide water extracted by the actuator 112. The droplet collector 122 can be positioned to capture water that is released from the moisture-harvesting material 116 during vibrational actuation, directing the extracted moisture toward collection reservoirs or processing systems. The droplet collector 122 can include channels, funnels, or other fluid guidance structures that facilitate efficient water collection while minimizing losses due to evaporation or misdirection. The design of the droplet collector 122 can account for the specific characteristics of water release during vibrational extraction, which may include both liquid droplets and vapor phases depending on the actuation parameters and sorbent properties.Attorney Docket No. MIT 25345 PCT | 88212-427691

[0077] The system 100 can include an in-situ sensor 123 that can monitor transient changes in properties of the moisture-harvesting material 116 and provide feedback to at least one of the actuator 112 or the electrical circuit 114 in view of the monitored transient changes in properties. The in-situ sensor 123 can continuously monitor parameters such as moisture content, mechanical properties, temperature, or other characteristics of the moistureharvesting material during operation. The sensor feedback can enable dynamic optimization of actuation parameters including frequency, amplitude, and duty cycle based on real-time assessment of sorbent conditions. This feedback mechanism can improve system efficiency by adjusting operational parameters to match the current state of the moisture -harvesting material 116, thereby ensuring optimal extraction performance while minimizing energy consumption.

[0078] In some embodiments, the actuator 112 can be configured to dynamically monitor the moisture-harvesting material 116 and provide feedback to the electrical circuit 114 in view of the same. The actuator 1 12 can function as both an actuation device and a sensing element through impedance monitoring or other electrical measurement techniques that correlate with moisture content or mechanical properties of the sorbent material. This dual functionality can eliminate use of separate sensing components while providing continuous monitoring capabilities throughout the extraction process. The system 100 can include one or more additional sensors 123 that dynamically monitor a moisture content of the moistureharvesting material 116 and provide feedback to at least one of the actuator 112 or the electrical circuit 114 in view of the same. These additional sensors 123 can provide complementary monitoring capabilities that enhance the precision and reliability of the feedback control system, enabling more sophisticated optimization of extraction parameters based on multiple measurement inputs.

[0079] Referring to FIG. 3 A, an embodiment of a moisture-harvesting device or system 210 is illustrated that features enhanced water collection capabilities through a dual enclosure configuration. The device 210 can include features similar to those discussed with respect to the system 110 above, and a detailed discussion of these features is omitted for the sake of brevity. As shown in FIG. 3 A, the device 210 can include an actuator 212, an electrical circuit 214, and a membrane 218.

[0080] The device 210 can include two enclosures, e.g., top and bottom enclosures 222a, 222b for water collection, providing increased collection capacity and improved operational efficiency compared to single-enclosure designs. The top and bottom enclosures 222a,Attorney Docket No. MIT 25345 PCT | 88212-427691222b can simultaneously collect water extracted by the actuator during vibrational actuation processes. The dual enclosure arrangement can enable continuous water collection from multiple extraction points, maximizing the capture of moisture released from the sorbent material during actuation cycles.

[0081] The enclosures may be positioned to collect water extracted by the actuator through different pathways, with the top enclosure 222a capturing water droplets or vapor that may be ejected upward during vibrational actuation, while the bottom enclosure 222b collects water that drains downward through gravitational forces. Each enclosure can be designed with appropriate collection surfaces, drainage channels, or condensation features that facilitate efficient water capture and retention. The dual enclosure configuration can accommodate different phases of water extraction that may occur during vibrational actuation, including both liquid droplet formation and vapor condensation processes. The enclosures 222a, 222b may be fabricated from materials that promote water collection while providing adequate structural integrity to withstand the mechanical forces generated during actuator operation.

[0082] As further shown in FIG. 3 A, the whole system 210 can be housed within a mechanical support structure 224 that provides structural stability and component organization for the atmospheric water harvesting device. The mechanical support structure224 can include a 3D-printed support structure that can be fabricated using additive manufacturing techniques to achieve precise dimensional control and customized geometries tailored to specific system requirements. The 3D-printed support structure 224 can enable rapid prototyping and design iteration while providing cost-effective manufacturing for both research and commercial applications. The support structure 224 can be designed to accommodate various actuator configurations, sorbent geometries, and collection system arrangements while maintaining proper alignment and mechanical stability during operation.

[0083] The mechanical support structure 224 can include a supporting tripod 225 that provides a stable base for the atmospheric water harvesting system. The supporting tripod225 can distribute the weight of the system components across multiple contact points, reducing stress concentrations and improving overall stability during vibrational actuation. The tripod 225 configuration can enable the system 210 to be positioned on various surfaces while maintaining proper orientation of the actuator and collection components 222a, 222b. The supporting tripod 225 may be adjustable to accommodateAttorney Docket No. MIT 25345 PCT | 88212-427691 different installation requirements or to optimize the positioning of the system 200 relative to ambient airflow patterns that affect moisture capture efficiency.

[0084] The mechanical support structure 224 also includes a support platform 232 that can provide a mounting surface for the actuator 212 and associated components. The support platform 232 can be designed to accommodate specific actuator geometries while providing adequate mechanical coupling for efficient vibrational energy transfer to the moistureharvesting material. The platform 232 may include mounting features such as threaded inserts, alignment pins, or clamping mechanisms that secure the actuator in proper position relative to the sorbent material and collection enclosures. The support platform 232 can incorporate vibration isolation features that prevent unwanted energy losses while ensuring that vibrational energy is directed toward the moisture extraction process rather than being dissipated through the support structure 224.

[0085] The mechanical support structure 224 further comprises top and bottom insulators 226, 228 that can provide thermal and vibrational isolation between different system components. The top insulator 226 can reduce heat transfer from external sources that might affect the temperature-sensitive performance of the moisture-harvesting material 116, while the bottom insulator 228 can minimize vibrational coupling between the actuator 212 and the supporting surface 224. The insulators 226, 228 may be fabricated from materials with appropriate thermal and mechanical properties to achieve desired isolation characteristics while maintaining structural integrity. The insulation components 226, 228 can also reduce acoustic noise transmission from the vibrational actuator to the surrounding environment, improving the suitability of the system for residential or commercial applications where noise levels may be a concern.

[0086] A wire track 230 can be incorporated within the mechanical support structure 224 to provide organized routing for electrical connections between system components. The wire track 230 can guide electrical cables from the actuator 212 to the driving circuit 214 while protecting the connections from mechanical damage during system operation or maintenance activities. The wire track 230 may include features such as strain relief, cable management clips, or protective covers that ensure reliable electrical connectivity throughout the operational lifetime of the system 210. The organized cable routing provided by the wire track 230 can also facilitate system assembly and disassembly for maintenance or component replacement procedures.Attorney Docket No. MIT 25345 PCT | 88212-427691

[0087] FIG. 3B illustrates a system 200 having two assembled devices 210 that display a practical implementation of the moisture-harvesting device 210 illustrated in FIG. 3 A. FIG. 3B shows each assembled device 210 connected to its respective electronic circuit 214 during the process of moisture collection, illustrating the operational configuration of the atmospheric water harvesting technology. The assembled devices 200 demonstrate the integration of the mechanical support structure, dual enclosure configuration, and electronic control components in a functional device capable of extracting moisture from ambient air through vibrational actuation.

[0088] The electronic circuits 214 shown in FIG. 3B provide the electrical power and control signals necessary to drive the actuators 212 in each system during moisture collection operations. Each electronic circuit 214 can be configured to deliver specific frequency, amplitude, and duty cycle parameters that optimize the vibrational actuation for the particular moisture-harvesting material 116 and environmental conditions present during operation. The circuits 214 may include monitoring capabilities that track system performance and adjust operational parameters in real-time to maintain optimal extraction efficiency. The connection between each assembled device 210 and its respective electronic circuit 214 can enable independent operation of multiple atmospheric water harvesting units, allowing for scalable deployment in applications requiring higher water production rates or redundant operation capabilities. Water droplets after desorption are shown in inset (i).

[0089] FIG. 3C presents a graph showing the energy efficiency of water extraction rj, which is defined as a ratio of the enthalpy of water vaporization htvhlv= 2.257 MJ / kg at o100 C) and the energy consumption of the device needed for the extraction of a unit mass of water from a sorbent, E [MJ / kg]:7 = hiv / E

[0090] In particular, FIG. 3C compares the efficiency of the device 210 operated with a polyacrylamide and lithium chloride (PAM-LiCl) hydrogel sorbent with that of the-state-of- the-art AWH devices. In particular, FIG. 3C illustrates efficiency values of moisture extraction achieved with components of the instant device 210 as compared to literature data. The extraction efficiency values plotted in FIG. 3C for different systems account for the specific heat of both water and other solids used in the system (i.e., sorbent materials, heaters, enclosures, etc.) as well as heat dissipation losses. As such, they can depend, at least in part,Attorney Docket No. MIT 25345 PCT | 88212-427691 on the choice of materials and / or the desoiption (regeneration) temperature of each AWH device. Each of the devices in FIG. 3C represents a single-stage system without heat recovery, and thus these efficiency values are all less than 100%.

[0091] It will be appreciated that the efficiency of the device 210 can vary based on the components used and / or the regime in which the components are running. For example, a cycle of actuation of the components can impact efficiency of moisture extraction. As discussed below with respect to FIG. 11 , efficiency of moisture extraction can be influenced by length of actuation cycle run times for components of the device. FIG. 2C illustrates energy efficiency for the devices (1) and arrays (2) of the present embodiments under short actuation periods, e.g., about 2-minute-long cycle operation, the devices (3) and arrays (4) of the present embodiments under long actuation periods, e.g., longer than 2-minute-long cycle operation, and an average efficiency of the device under multiple repetitive cycle of short activation periods, e.g., about 2-minute-long cycle operation. In some embodiments of the present device 210, a demonstrated energy efficiency of almost 47% can be observed.Moreover, as shown, the device 210 can demonstrate an energy efficiency of almost 428%, exceeding the state-of-the-art efficiency of 9.5% by a factor of ~45. The improved performance of the device operating under multiple repetitive cycles of short activation periods in (5) can highlight the increased benefits of the device 210 of the present embodiments. Moreover, it will be appreciated that the sensors 123 can be utilized in conjunction with the cycle of actuation in (5) to sense the time at which the most efficient condition is reached, which can be used to optimize timing of the short activation periods to achieve optimal energy efficiency.

[0092] As further shown in FIG. 3C, the energy efficiency data points for conventional atmospheric water harvesting systems can demonstrate that most existing technologies operate at efficiency levels below 20%, with many systems exhibiting efficiencies in the range of about 5% to about 15% due to energy losses associated with heating, heat transfer, and thermal management requirements. The wide distribution of efficiency values among conventional systems can reflect the challenges associated with optimizing thermal extraction processes while maintaining practical operational characteristics such as reasonable extraction rates, system durability, and cost-effectiveness.

[0093] FIGS. 4A-4C illustrate an ultrasonic actuator or actuator assembly 212 of the device 210 of the present embodiments in greater detail. As shown, the actuator 212 can include individual components that demonstrate the practical implementation of piezoelectricAttorney Docket No. MIT 25345 PCT | 88212-427691 transduction for atmospheric water harvesting applications. FIGS. 4A-4C show the detailed construction of an ultrasonic actuator 212 that includes at least one piezoelectric element 234 that can serve as a primary transduction component for converting electrical energy into mechanical vibrations combined with a stainless-steel porous membrane 236 through which desorbed water can be extracted from a sorbent material under vibrational actuation, as discussed in greater detail below.

[0094] The actuator 212 structure represents a complete assembly that integrates multiple functional components to achieve efficient moisture extraction through piezoelectric actuation mechanisms. The piezoelectric element 234 can include a lead zirconate titanate (PZT)-crystal piezoelectric transducer, or at least one of inorganic piezoelectric materials that provide superior electromechanical performance compared to organic or polymer-based alternatives, that can leverage the indirect piezoelectric effect present in non-centrosymmetric crystal structures to generate mechanical stress and vibrational waves, e.g.. high frequency pressure waves 239, such as those used for ultrasound stimulation 241 (as shown in FIG. 5E) when subjected to alternating electrical fields. The piezoelectric element 234 can operate across a range of frequencies extending from audible sound frequencies to ultrasonic frequencies, with particular effectiveness demonstrated in the ultrasonic range around 110 kHz for moisture extraction applications. The piezoelectric element 234 can exhibit high electromechanical coupling coefficients that maximize energy transduction efficiency while minimizing losses to heat generation during operation. It will be appreciated that PZT materials can achieve piezoelectric charge coefficients that enable efficient conversion of electrical energy to mechanical displacement, making PZT particularly suitable for applications requiring high-amplitude vibrational actuation such as moisture extraction from sorbent materials.

[0095] The piezoelectric element 234 may alternatively include barium titanate, which provides piezoelectric properties with different temperature stability characteristics compared to PZT materials. Barium titanate can offer advantages in applications where environmental temperature variations may affect piezoelectric performance, providing more stable electromechanical coupling across broader temperature ranges. The piezoelectric element may also comprise zinc oxide, which can be fabricated in thin film configurations that enable integration into compact actuator assemblies while maintaining effective piezoelectric response. Zinc oxide materials can provide piezoelectric actuation capabilities with reduced material costs compared to PZT ceramics, making zinc oxide suitable for applications whereAttorney Docket No. MIT 25345 PCT | 88212-427691 economic considerations are paramount. In some embodiments, the piezoelectric element 234 may include lithium niobate. The selection of specific inorganic piezoelectric materials can be optimized based on the particular requirements of the atmospheric water harvesting application, including factors such as operating frequency range, environmental conditions, power consumption constraints, and cost considerations.

[0096] With continued reference to FIGS. 4A-4C, the actuator structure can include one or more Ag-coated PZT rings 238 that can provide both piezoelectric functionality and electrical connectivity for the actuator assembly 112. The silver coating 238 on the PZT ring can serve as an electrode surface that enables efficient electrical contact with the driving circuit while providing corrosion resistance in the humid operating environment of atmospheric water harvesting systems. The Ag-coated PZT ring 238 can be fabricated with precise dimensional tolerances that ensure proper mechanical coupling with other actuator components while maintaining electrical isolation between electrode surfaces. The ring geometry of the PZT element 234 can enable uniform distribution of electrical fields across the piezoelectric material, promoting consistent vibrational amplitude throughout the surface of the actuator 212.

[0097] The actuator 212 can include a thin layer of water-resistant resin 240 that can be positioned on top of the Ag-coated PZT ring 238 to provide environmental protection for the piezoelectric element 234. The water-resistant resin 240 can prevent moisture infiltration into the piezoelectric material 234 that can degrade electromechanical performance or cause electrical short circuits during operation. The resin layer 240 can be formulated to maintain flexibility that accommodates the mechanical deformations of the PZT element during vibrational actuation while providing adequate sealing against water penetration. The thickness and material properties of the water-resistant resin 240 can be optimized to minimize interference with vibrational energy transmission while ensuring long-term protection of the piezoelectric element.

[0098] The stainless-steel porous membrane 236 can facilitate the extraction of desorbed water from the sorbent material during vibrational actuation. The stainless-steel porous membrane 236 can provide mechanical support for the moisture-harvesting material while allowing extracted water to pass through the membrane perforations for collection. The stainless-steel construction can offer corrosion resistance and mechanical durability that can withstand repeated actuation cycles without degradation of the membrane structure. The porous membrane 236 can be fabricated with controlled pore sizes and distributions thatAttorney Docket No. MIT 25345 PCT | 88212-427691 optimize water extraction efficiency while maintaining adequate mechanical strength to support the sorbent material during vibrational actuation.

[0099] The actuator assembly 112 can be encased in a silicone elastomeric ring 242 that can provide additional environmental sealing and mechanical protection for the internal components. The silicone elastomeric ring 242 can accommodate thermal expansion and mechanical deformations of the actuator components during operation while maintaining effective sealing against moisture infiltration. The elastomeric properties of the silicone ring 242 can enable the actuator 212 to maintain proper mechanical coupling with the moistureharvesting material while providing vibration isolation that prevents energy losses to the surrounding support structure. The silicone encasement can be formulated with specific durometer properties that optimize the balance between sealing effectiveness and mechanical compliance for efficient vibrational energy transmission.

[0100] The complete actuator assembly demonstrated in FIGS. 4A-4C can operate at ultrasonic frequencies of about 110 kHz, which represents a frequency range in which moisture can be efficiently extracted from hydrogel sorbent materials. The 1 10 kHz operating frequency can enables the actuator 212 to generate sufficient vibrational energy to disrupt water-sorbent interactions while maintaining energy efficiency that significantly exceeds conventional thermal extraction methods. The ultrasonic frequency operation can produce mechanical vibrations with wavelengths that can effectively penetrate the sorbent material structure, ensuring that water molecules bound in interior regions of the moistureharvesting material 116 experience adequate vibrational forces to promote release. The actuator assembly 112 can maintain stable operation at the 110 kHz frequency while delivering consistent vibrational amplitude that enables reliable moisture extraction performance across varying environmental conditions and sorbent moisture content levels.

[0101] FIGS. 5A-5F illustrate the individual components of the assembly of the actuator 212 and the mesh 218 that can enable optimized moisture extraction through controlled permeability and electrode functionality. FIGS. 5A-5F show the detailed construction of the mesh components or membrane components 218 that can be integrated with the ultrasonic actuator to facilitate water extraction from sorbent materials while providing electrical connectivity for system operation. As discussed with respect to FIGS. 2A-2B above, the mesh components 218 can represent important interface elements that control the interaction between the vibrational actuator 212 and the moisture-harvesting material 116, enabling efficient energy transfer while facilitating water collection and removal processes.Attorney Docket No. MIT 25345 PCT | 88212-427691

[0102] The membrane component 218 can be fabricated with zero perforations to provide a continuous surface that maximizes vibrational energy transfer from the actuator 212 to the moisture-harvesting material 116. The non-perforated membrane 218 configuration can enable uniform distribution of mechanical forces across the entire contact surface between the actuator 212 and the sorbent material 116 that collects atmospheric moisture 243, ensuring consistent vibrational amplitude throughout the moisture-harvesting material volume. The continuous membrane surface can provide enhanced mechanical coupling that minimizes energy losses during vibrational transmission while maintaining structural integrity under repeated actuation cycles. The zero perforation configuration may be particularly suitable for applications where maximum vibrational energy transfer is desired and where water extraction occurs primarily through alternative pathways such as edge drainage or vapor collection.

[0103] As shown in FIG. 5B and FIG. 4C, the membrane component 218 can alternatively be fabricated with multiple perforations or nozzles 244 that enable direct water extraction through the membrane structure during vibrational actuation. The multiple perforation configuration provides controlled pathways for extracted water to pass through the membrane 218 while maintaining adequate structural support for the moisture-harvesting material 116. The perforations can be distributed across the membrane surface in patterns that optimize both water extraction efficiency and mechanical stability of the membrane structure. The perforation density and distribution can be tailored to match the specific characteristics of the moisture-harvesting material 116 and the expected water release patterns during vibrational actuation.

[0104] Referring back to FIGS. 4A-4C, the nozzle structures 244 integrated within the membrane 218 can be fabricated with precise dimensional control to achieve optimal water extraction performance. The nozzle sizes can approximately range from about 10 pm to about 100 pm in diameter, providing a range of aperture dimensions that accommodate different water extraction mechanisms and sorbent material characteristics. The smaller nozzle sizes around 10 pm can enable extraction of water in fine droplet form 246 while providing high surface tension effects that can facilitate controlled water release from the sorbent material 116. The larger nozzle sizes that approach 100 pm can allow for extraction of larger water droplets 248 or clusters that may form during vibrational actuation of high- capacity sorbent materials, while the intermediate nozzle sizes, e.g., between 10 pm and 100 pm, can provide flexibility in optimizing water extraction characteristics for specific sorbentAttorney Docket No. MIT 25345 PCT | 88212-427691 materials and operating conditions. Nozzle sizes around 25-50 pm can provide balanced performance that accommodates both fine droplet extraction and larger water cluster removal while maintaining adequate membrane structural integrity. The selection of appropriate nozzle sizes can be based on the pore structure and water binding characteristics of the moisture-harvesting material 116, with smaller nozzles suitable for materials that release water in fine droplet form and larger nozzles appropriate for materials that generate larger water clusters during vibrational actuation.

[0105] With continued reference to FIGS. 5A-5F, the membrane components 218 can exhibit ion-solution permeability characteristics that can enable selective transport of water while potentially retaining dissolved salts or other components within the sorbent material 116. The ion-solution permeability can be controlled through the nozzle size selection and membrane material properties to achieve desired separation characteristics during water extraction. Smaller nozzle sizes may provide enhanced selectivity for water transport while restricting the passage of larger ionic species or dissolved components that may be present in the moisture-harvesting material. The permeability characteristics can be particularly relevant for sorbent materials that incorporate hygroscopic salts or other dissolved components that should be retained within the sorbent structure during water extraction processes. In some embodiments, microscopic analysis can be performed to reveal surface features such as nozzle edge sharpness, surface roughness, and pore uniformity that influence the fluid dynamics of water extraction during vibrational actuation. Imaging techniques can also be used to identify any surface modifications or treatments that may be applied to the membrane 218 to enhance water extraction efficiency or improve compatibility with specific sorbent materials.

[0106] As discussed with the respect to the embodiments above, the membrane components 218 can be configured to operate as electrodes for at least one of the actuator 212 or the electrical circuit 214, providing dual functionality that combines mechanical support with electrical connectivity. When functioning as an electrode, the membrane 218 can be fabricated from electrically conductive materials that enable current flow while maintaining the mechanical and permeability characteristics required for water extraction. In some embodiments, the membrane 218 can be integrated directly into the electrical circuit that drives the actuator 212, providing both the mechanical interface for vibrational energy transfer and the electrical pathway for actuator control. In some embodiments, the membraneAttorney Docket No. MIT 25345 PCT | 88212-427691218 can enable the component to serve as either a positive or negative electrode in the electrical circuit that drives the piezoelectric actuator.

[0107] The actuator 212 may include multiple arrays of piezoelectric elements arranged in various geometries that enable distributed vibrational energy delivery to the sorbent material through coordinated actuation mechanisms. FIGS. 6A-6F exhibit different types of piezo array geometries that can be used for water extraction using the system architectures of the present disclosure, demonstrating the versatility and scalability of piezoelectric actuation for atmospheric water harvesting applications. The array configurations provide enhanced coverage area and improved energy distribution compared to single-element actuators, enabling more uniform vibrational actuation across larger volumes of moisture-harvesting material. The distributed nature of array actuators can accommodate various sorbent geometries and configurations while maintaining effective vibrational coupling throughout the moisture extraction process.

[0108] FIG. 6A shows a ID array configuration 250 where piezoelectric elements 234 are arranged in a linear sequence that provides directional vibrational energy distribution along a single axis. The ID array 250 can enable the system 210 to deliver coordinated vibrational actuation across elongated sorbent configurations or to create directional wave propagation patterns that enhance moisture extraction efficiency in specific regions of the moisture-harvesting material. The linear arrangement of piezoelectric elements in the ID array can be controlled with phase relationships that create constructive or destructive interference patterns, enabling selective enhancement or suppression of vibrational energy in different regions of the sorbent material. The ID array configuration 250 may be particularly suitable for applications where the moisture-harvesting material has an elongated geometry or where directional water extraction is desired to facilitate collection processes.

[0109] As further shown in FIG. 6B, a 1.5D array configuration 252 can provide enhanced spatial control compared to linear I D arrays while maintaining relatively simple control requirements. The 1.5D array 252 can incorporate additional piezoelectric elements that enable limited two-dimensional control of vibrational energy distribution, providing improved coverage of irregularly shaped sorbent materials or enabling focused energy delivery to specific regions where moisture extraction may be most effective. The 1.5D array can accommodate sorbent materials with moderate geometric complexity while avoiding the control complexity associated with full two-dimensional array configurations. TheAttorney Docket No. MIT 25345 PCT | 88212-427691 intermediate complexity of the 1.5D array 250 can enable cost-effective implementation while providing enhanced performance compared to simple linear array configurations.

[0110] FIG. 6C shows a 2D array configuration 254 that provides comprehensive spatial control of vibrational energy distribution across two-dimensional surfaces or volumes of moisture-harvesting material. The 2D array 254 can enable the system 210 to create complex vibrational patterns that can be tailored to match the specific characteristics of different sorbent materials or to optimize extraction efficiency for particular environmental conditions. The two-dimensional arrangement of piezoelectric elements can allow for sophisticated control strategies including beam steering, focal point control, and adaptive pattern generation that can respond to real-time feedback from moisture content sensors or other monitoring systems. The 2D array configuration 254 can provide maximum flexibility in vibrational energy delivery while enabling advanced control algorithms that optimize extraction performance based on dynamic operating conditions.

[0111] FIG. 6D shows an annular array configuration 256 where piezoelectric elements 234 are arranged in a circular pattern that provides radially symmetric vibrational energy distribution. The annular array 234 can enable uniform actuation of cylindrical or spherical sorbent configurations while creating focused vibrational energy patterns that converge toward the center of the array geometry. The circular arrangement of piezoelectric elements 234 can generate standing wave patterns or rotating vibrational modes that enhance moisture extraction through complex mechanical interactions with the sorbent material structure. The annular array configuration 234 may be particularly effective for applications where the moisture-harvesting material 116 is contained within cylindrical vessels or where radial symmetry in vibrational energy distribution provides optimal extraction performance.

[0112] FIG. 6E shows a circular phased array configuration 258 that combines the radial symmetry of annular arrays 256 with sophisticated phase control capabilities that enable dynamic beam steering and focal point manipulation. The circular phased array 258 can create highly focused vibrational energy patterns that can be electronically steered to different locations within the sorbent material without mechanical movement of the actuator assembly. The phased array 258 control can enable the system 210 to sequentially target different regions of the moisture -harvesting material during extraction cycles, potentially improving overall extraction efficiency by ensuring that all regions of the sorbent experience optimal vibrational energy levels.Attorney Docket No. MIT 25345 PCT | 88212-427691

[0113] As further illustrated in FIG. 6F, a 2D segmented annular array configuration 260 can combine the benefits of two-dimensional spatial control with the radial symmetry advantages of annular array geometries. The segmented annular array 260 can enable independent control of different angular sectors within the circular array pattern, providing both radial and angular control of vibrational energy distribution. The segmentation can allow the system 210 to create asymmetric vibrational patterns that can accommodate non- uniform moisture distribution within the sorbent material or compensate for geometric irregularities in the moisture-harvesting material configuration. The 2D segmented annular array 260 can provide comprehensive spatial control capabilities while maintaining the focused energy delivery characteristics that make annular arrays effective for moisture extraction applications.

[0114] The actuator 212 can include at least one of piezoelectric films or fiber-based scaffolds that provide flexible implementation options for integrating vibrational actuation capabilities into various sorbent material configurations. Piezoelectric films can be fabricated as thin, flexible sheets that can conform to curved or irregular sorbent geometries while maintaining effective electromechanical coupling for vibrational energy generation. The film configuration can enables the actuator 212 to be integrated directly into the structure of the moisture-harvesting material 1 16, providing distributed actuation throughout the sorbent volume rather than surface-only actuation. Fiber-based scaffolds can be woven, braided, or otherwise integrated into the sorbent material structure to create three- dimensional networks of piezoelectric elements that provide comprehensive vibrational energy distribution throughout the moisture-harvesting material volume.

[0115] The piezoelectric films or fiber-based scaffolds may comprise polymer piezoelectric materials that offer advantages in terms of flexibility, processability, and environmental compatibility compared to ceramic piezoelectric materials. Polymer piezoelectric materials can be fabricated into complex geometries and integrated into composite structures more readily than rigid ceramic materials, enabling innovative actuator configurations that maximize the interface area between the piezoelectric elements and the moisture-harvesting material. The polymer materials can also provide improved mechanical compatibility with flexible sorbent materials such as hydrogels, reducing stress concentrations and mechanical failures that might occur with rigid ceramic actuators.

[0116] The polymer piezoelectric materials may include poly vinylidene fluoride (PVDF), which can be processed into thin films, fibers, or complex three-dimensionalAttorney Docket No. MIT 25345 PCT | 88212-427691 structures that provide effective piezoelectric response while maintaining flexibility and durability in humid operating environments. The PVDF material can achieve piezoelectric coefficients that enable effective vibrational actuation for moisture extraction while providing long-term stability under repeated actuation cycles. Some additional non-limiting examples of these materials can include polyvinylidene fluoride-trifluoroethylene (PVDF-TrFE) copolymer, which provides enhanced piezoelectric properties compared to pure PVDF materials, poly-l-lactic acid (PLLA), polyacrylonitrile (PAN), which can be processed into fiber configurations that provide distributed piezoelectric actuation throughout the volume of the moisture-harvesting material, nylon, and / or silk, among others.

[0117] The array configurations shown in FIGS. 6A-6F enable distributed vibrational energy delivery to the sorbent material through coordinated actuation of multiple piezoelectric elements operating in synchronized or phase-controlled patterns. The distributed energy delivery can create tailored uniform vibrational fields throughout the moisture-harvesting material volume, ensuring that water molecules bound in different regions of the sorbent experience consistent mechanical forces that promote release. The array actuators can operate with controlled phase relationships between individual elements that create constructive interference patterns in regions where enhanced extraction is desired, while potentially creating destructive interference in regions where vibrational energy should be minimized. The coordinated operation of array elements can enable sophisticated control strategies that can adapt to changing moisture distribution patterns within the sorbent material during extraction cycles, optimizing energy utilization while maximizing water recovery rates.

[0118] Referring to FIGS. 7A and 7B, the actuator-sorbent assembly demonstrates alternative configurations that enable moisture extraction through vibrational actuation by trapping and amplifying audible acoustic waves. For example, FIGS. 7A and 7B illustrate a schematic representation of a device 310 that can operate under alternating voltage supplied through electrical contacts, showing the practical implementation of vibrational actuation systems that accommodate various operational requirements and environmental constraints. The device 310 can provide flexibility in system configuration by enabling operation with or without nozzle membranes in the audible frequency range, allowing optimization of water extraction characteristics based on specific sorbent materials and operating conditions

[0119] For example, the device 310 can operate under alternating voltage that is supplied through electrical contacts 314 integrated into the assembly structure. The electrical contactsAttorney Docket No. MIT 25345 PCT | 88212-427691314 can provide reliable connectivity for delivering power from the driving circuit to the actuator elements while maintaining proper electrical isolation and safety characteristics during operation. The alternating voltage supply enables precise control of actuation frequency, amplitude, and duty cycle parameters that optimize vibrational energy delivery to the moisture-harvesting material. The electrical contacts 314 may be configured to accommodate various voltage levels and current requirements depending on the specific actuator configuration and power requirements of the atmospheric water harvesting system.

[0120] As further shown in FIGS. 7 A and 7B, the device 310 may operate without nozzle membranes, providing unobstructed vibrational energy transfer to the moistureharvesting material while relying on alternative water collection mechanisms. The configuration without nozzle membranes can enable maximum vibrational coupling between the actuator 312 and sorbent material 116, potentially improving extraction efficiency in applications where water collection can be accomplished through edge drainage, vapor capture, or other collection methods that do not require direct perforation of the actuatorsorbent interface. The membrane-free configuration may also reduce manufacturing complexity and cost while providing enhanced mechanical durability by eliminating potential failure points associated with perforation structures.

[0121] The actuator demonstrated in FIGS. 7A and 7B operates within the audible frequency range, providing vibrational actuation capabilities that generate sound frequencies perceptible to human hearing. The audible frequency operation can enable the system 310 to utilize acoustic energy in the frequency range from approximately about 20 Hz to about 20 kHz, encompassing the full spectrum of human auditory perception. The audible frequency range can include optimal extraction frequencies at around 150 Hz that have been demonstrated to provide superior energy efficiency for moisture extraction from hydrogel materials. The audible frequency operation can also encompass higher frequency ranges approaching the ultrasonic threshold, enabling the system to access multiple optimal extraction frequency bands within a single actuator configuration.

[0122] As shown, the actuator 312 can include one or more acoustic speakers that provide vibrational actuation through conventional audio transduction mechanisms adapted for moisture extraction applications. Acoustic speakers can generate controlled vibrational energy across the audible frequency spectrum while enabling the device 310 to utilize existing audio amplification and control technologies and generating sound frequencies and amplitude levels that are compatible with human auditory comfort and environmental noiseAttorney Docket No. MIT 25345 PCT | 88212-427691 regulations. The speaker-based actuator can operate at sound pressure levels that provide effective moisture extraction while remaining within acceptable noise limits for residential, commercial, or public environments. The audible frequency operation allows the system to utilize music, tones, or other acoustically pleasant waveforms that provide both functional moisture extraction capabilities and aesthetic appeal for human operators or bystanders. The public-friendly operation characteristics make the atmospheric water harvesting system suitable for deployment in populated areas where conventional industrial equipment noise might be objectionable or prohibited by local regulations.

[0123] With continued reference to FIGS. 7A and 7B, the speaker-based actuator configuration enables the system to utilize actual music tracks or audio content that contains frequency components in the optimal extraction ranges identified for moisture harvesting applications. Music tracks with substantial bass content around about 150 Hz can provide effective vibrational actuation while creating an aesthetically pleasant operational environment that masks the industrial nature of the moisture extraction process.

[0124] The acoustic speaker actuator 312 can accommodate various audio input sources including digital music players, radio receivers, or custom waveform generators that provide optimized frequency content for moisture extraction performance. The speaker configuration can enable real-time adjustment of frequency content and amplitude levels based on environmental conditions, time of day, or local noise regulations, providing adaptive operation that maintains both extraction performance and community compatibility.

[0125] In some embodiments, the actuator 312 can include cage-like structures 316, as shown in FIG. 7C, which provide distributed vibrational actuation throughout the volume of the moisture-harvesting material while allowing extracted water to escape through openings in the cage framework. The cage actuator configuration can enable three-dimensional distribution of vibrational energy throughout the sorbent volume 116 rather than limiting actuation to surface contact areas. The cage structure can be fabricated with controlled opening sizes and distributions that facilitate water extraction while maintaining structural integrity and vibrational coupling with the moisture-harvesting material. The cage-like geometry provides mechanical support for the sorbent material during vibrational actuation while creating multiple pathways for water escape that prevent accumulation of extracted moisture within the actuator assemblyAttorney Docket No. MIT 25345 PCT | 88212-427691

[0126] The cage actuator framework can be fabricated from materials that provide both structural support and vibrational transmission capabilities, enabling the cage structure itself to serve as a mechanical waveguide that distributes vibrational energy throughout its framework. The cage materials may include metals, polymers, or composite materials that exhibit appropriate mechanical properties for vibrational transmission while providing adequate strength and durability for repeated actuation cycles. The cage structure can be designed with controlled mechanical resonance characteristics that enhance vibrational energy transmission at specific frequencies that optimize moisture extraction performance. The resonant properties of the cage framework can be tuned through geometric design and material selection to match the optimal extraction frequencies identified for specific sorbent materials and operating conditions.

[0127] Referring to FIG. 8, the process of engineering nano / micro-architectured or configured scaffolds 320 and integrating them within sorbent materials 116 demonstrates advanced fabrication techniques that can enable enhanced vibrational energy transmission and mechanical stability for atmospheric water harvesting applications. As shown, the moisture-harvesting material 116 may encapsulate an active scaffold 320 that is configured to serve as the actuator, or as an additional actuator, providing integrated vibrational actuation capabilities directly within the sorbent material structure. The scaffold engineering process can enable the creation of composite structures or scaffold-supported sorbent 322 where architectured support elements are distributed throughout or embedded within the sorbent volume to optimize both moisture capture and extraction performance. The integration methods shown can provide flexibility in tailoring scaffold geometry, porosity, and distribution within the sorbent to achieve desired mechanical properties and vibrational transmission characteristics. The active scaffold configuration can represent a departure from external actuator arrangements by integrating the vibrational energy generation directly within the moisture-harvesting material 116, enabling distributed actuation throughout the sorbent volume rather than relying solely on surface-applied vibrational energy. The encapsulated active scaffold approach can provide enhanced vibrational coupling and improved extraction efficiency by ensuring that mechanical energy is generated at multiple locations within the sorbent structure where water molecules are bound.

[0128] Some non-limiting examples of creation of the scaffold-supported sorbent 322 of the present embodiments that is within the scope of the present disclosure can include scaffold fabrication and integration that can be accomplished through various methodsAttorney Docket No. MIT 25345 PCT | 88212-427691 including grafting, plying, twisting, braiding, pore infiltration, solution dipping or casting, cross-linking, and 3D printing processes. For example, the scaffold-supported sorbent 322 can include a 3D printed structure that provides precise geometric control and customized architectures tailored to specific system requirements and sorbent material characteristics. 3D printed scaffold structures can be fabricated using additive manufacturing techniques that enable complex internal geometries and controlled porosity distributions that optimize both mechanical support and vibrational energy transmission throughout the sorbent volume. The 3D printing process allows for rapid prototyping and design iteration of scaffold configurations, enabling optimization of structural parameters such as stmt thickness, pore size, and connectivity patterns that influence both mechanical stability and acoustic properties. 3D printed scaffolds can incorporate features such as resonant cavities, waveguide structures, or impedance matching elements that enhance vibrational energy coupling between the actuator and the moisture-harvesting material.

[0129] Tn some embodiments, the scaffold 320 may alternatively include a wire grid that provides distributed mechanical support while creating pathways for vibrational energy transmission throughout the sorbent material. Wire grid scaffolds can be fabricated from metallic or polymeric materials that can exhibit appropriate mechanical properties for supporting the sorbent structure while providing effective acoustic coupling for vibrational energy propagation. The wire grid configuration can enable controlled spacing and orientation of support elements that can be optimized to match the mechanical requirements of specific sorbent materials while minimizing interference with moisture capture and extraction processes. Some additional non-limiting embodiments of the scaffold can include knitted or woven textiles that provide flexible mechanical support with controlled porosity and surface area characteristics that enhance both moisture capture and vibrational energy distribution, non-woven structures that can be fabricated through processes such as electrospinning, melt-blowing, or needle-punching that create interconnected fiber networks with tailored pore size distributions and mechanical properties, a plurality of fibers, yarns, braids, or rods that provide distributed mechanical reinforcement while creating pathways for vibrational energy propagation through the moisture -harvesting material volume.

[0130] The scaffold engineering process illustrated in FIG. 8 can enable chemical bonding between scaffold materials and sorbent polymers, creating integrated composite structures with enhanced interfacial adhesion and mechanical stability. Grafting processes can involve chemical functionalization of scaffold surfaces to promote covalent bonding withAttorney Docket No. MIT 25345 PCT | 88212-427691 sorbent materials, ensuring that mechanical loads and vibrational energy are effectively transferred across the scaffold-sorbent interface. The grafting approach can prevent delamination or separation of scaffold components during repeated moisture absorption and extraction cycles, maintaining structural integrity and performance throughout the operational lifetime of the atmospheric water harvesting system.

[0131] Pore infiltration techniques demonstrated in FIG. 8 enable the integration of scaffold materials into existing porous sorbent structures through controlled penetration and distribution processes. Pore infiltration can involve the introduction of scaffold particles, fibers, or precursor materials into the pore network of the sorbent material, creating distributed reinforcement throughout the sorbent volume. The infiltration process can be controlled to achieve desired scaffold distribution patterns that optimize both mechanical support and vibrational energy transmission without significantly reducing the moisture capture capacity of the sorbent material. Pore infiltration techniques can accommodate various scaffold material types and sizes, enabling customization of composite properties based on specific application requirements.

[0132] Solution dipping and casting processes illustrated in FIG. 8 can enable the creation of composite sorbent-scaffold structures through controlled deposition and solidification of scaffold materials within or around the sorbent matrix. Solution dipping can involve immersion of porous sorbent materials in solutions containing scaffold precursors that penetrate the pore network and solidify to create distributed reinforcement structures. Casting processes can involve the simultaneous formation of sorbent and scaffold components through controlled polymerization or solidification of mixed precursor solutions. The solution-based integration techniques enable uniform distribution of scaffold materials throughout the sorbent volume while maintaining controlled porosity and surface area characteristics that optimize moisture capture and extraction performance.

[0013] The architectured moisture-harvesting material 1 16 may incorporate resonant shaping techniques that create geometric features designed to trap and amplify vibrational energy at specific frequencies that correspond to optimal moisture extraction conditions. Resonant shaping can involve the creation of periodic structures, cavity resonators, or other geometric features that exhibit mechanical resonances at frequencies that match the operating characteristics of the vibrational actuator. The resonant structures can concentrate vibrational energy in regions where moisture extraction is most effective while potentially suppressing unwanted vibrational modes that do not contribute to water releaseAttorney Docket No. MIT 25345 PCT | 88212-427691 mechanisms. The shaping techniques can be applied at multiple length scales, from macroscopic geometric features that influence overall material resonance to microscopic structures that affect local vibrational energy distribution within the sorbent volume.

[0134] Referring to FIGS. 9A-9D, the moisture-harvesting material 116 may be architectured or configured through advanced fabrication techniques to create specific geometric structures that trap and amplify vibrational modes for enhanced moisture extraction performance. FIGS. 9A-9D show embodiments where the sorbent itself is engineered with controlled architectures that enable the material to function as both a moisture capture medium and a vibrational energy manipulation system. The architectured sorbent configurations demonstrate how the moisture -harvesting material can be shaped and structured to achieve specific resonance frequencies that match the actuator driving frequencies, enabling enhanced vibrational coupling and improved extraction efficiency compared to unstructured sorbent materials.

[0135] FIGS. 9A-9D illustrate several embodiments where piezoelectric materials of various geometries are enclosed within sorbent materials to form the scaffold-supported sorbents 322 and act as scaffolds and / or actuators to facilitate vibration within the sorbent volume to enhance water extraction. As shown, variations of the scaffold-supported sorbents 322 can include at least one of a knitted textile 334 or woven textile 336, a non-woven structure, or a plurality of filaments 338, fibers 340, yarns, braids 342, films, bars, or rods 344 that provide distributed piezoelectric actuation throughout the moisture-harvesting material volume. Knitted textile 334 configurations can provide piezoelectric scaffolds with controlled porosity and mechanical flexibility that accommodate sorbent swelling and deformation during moisture absorption cycles while maintaining effective vibrational energy generation. The knitted structure 334 can incorporate piezoelectric fibers or yarns that are interlaced in patterns that optimize both mechanical support and electrical connectivity for actuator operation. Knitted piezoelectric scaffolds can provide anisotropic mechanical properties that enable controlled deformation patterns during vibrational actuation, potentially enhancing water release mechanisms through coordinated structural movements that complement the direct vibrational effects.

[0136] As further illustrated in FIGS. 10A and 10B, woven textile configurations can provide piezoelectric scaffolds with enhanced mechanical stability and controlled porosity characteristics that optimize both structural support and vibrational energy transmission. Woven piezoelectric textiles can incorporate both piezoelectric and non-piezoelectric fibersAttorney Docket No. MIT 25345 PCT | 88212-427691 in patterns that provide electrical connectivity while maintaining mechanical integrity and porosity required for moisture capture and extraction. The weaving pattern can be designed to create preferential directions for vibrational energy propagation while providing uniform mechanical support throughout the sorbent volume. Woven piezoelectric scaffolds can achieve higher mechanical strength compared to knitted configurations while maintaining adequate flexibility for integration within deformable sorbent materials such as hydrogels.

[0137] With continued reference to FIGS. 9A-9D, the scaffold-supported sorbents 322 can include a plurality of fibers 340 that provide distributed piezoelectric actuation through individual fiber elements integrated throughout the moisture-harvesting material structure. Piezoelectric fibers can be fabricated from polymer materials or polymer-ceramic composites that exhibit effective electromechanical coupling while maintaining the flexibility required for integration into various sorbent material configurations. The fiber diameter can range from nanometers (for nanofibers) to millimeters depending on the specific application requirements and sorbent material characteristics, with smaller fibers providing higher surface area contact and larger fibers providing enhanced mechanical support. Piezoelectric fibers can be oriented in specific directions to create anisotropic vibrational energy distribution or randomly distributed to provide isotropic actuation throughout the sorbent volume.

[0138] Plying and twisting techniques can enable the creation of composite scaffold structures 322 that combine multiple fiber or wire elements into integrated assemblies with controlled mechanical and acoustic properties. Twisting techniques can create helical scaffold structures that provide enhanced mechanical flexibility while maintaining effective acoustic coupling between the actuator and sorbent material. The twisted configuration can accommodate sorbent swelling and deformation during moisture absorption while preserving vibrational energy transmission pathways throughout the extraction process.

[0019] The piezoelectric scaffold configurations illustrated in FIGS. 9A-9D can enable the moisture-harvesting material to function as both a moisture capture medium and an integrated vibrational actuation system, eliminating the need for external actuator components while providing enhanced vibrational coupling throughout the sorbent volume. The encapsulated scaffold-supported sorbents 322 can improve extraction efficiency by ensuring that vibrational energy is generated directly within the regions where water molecules are bound to the sorbent material, reducing energy losses associated with vibrational transmission through interfaces between separate actuator and sorbentAttorney Docket No. MIT 25345 PCT | 88212-427691 components. The integrated actuation capability can enable more compact system designs while potentially reducing manufacturing complexity and cost compared to systems requiring separate actuator and sorbent assemblies.

[0140] The scaffold may comprise acoustic metamaterials designed to trap and amplify specific vibrational modes that optimize moisture extraction efficiency from the sorbent material. Acoustic metamaterial scaffolds can be engineered with periodic structures or resonant elements that create frequency-selective enhancement of vibrational energy at specific frequencies that correspond to optimal extraction conditions. The metamaterial design can incorporate features such as resonant cavities, Helmholtz resonators, or phononic crystal structures that manipulate acoustic wave propagation to concentrate vibrational energy in regions where moisture extraction is most effective. Acoustic metamaterial scaffolds can provide frequency -dependent amplification that enhances extraction efficiency at optimal operating frequencies while potentially suppressing unwanted vibrational modes that do not contribute to moisture release.

[0141] The acoustic metamaterial configuration enables selective enhancement of vibrational modes that correspond to the mechanical resonances of water-sorbent interactions, potentially improving extraction efficiency by matching the vibrational energy spectrum to the binding characteristics of water molecules within the sorbent structure. Metamaterial scaffolds can be designed to create localized field enhancement effects that concentrate vibrational energy in specific regions of the sorbent where moisture extraction is most effective. The periodic structure of acoustic metamaterials can create bandgap effects that prevent energy dissipation at unwanted frequencies while promoting energy concentration at frequencies that optimize moisture release mechanisms. Metamaterial scaffold designs can be customized based on the specific acoustic properties of different sorbent materials and the optimal extraction frequencies identified for particular moisture-harvesting applications.

[0142] The scaffold may be fabricated from photo-responsive materials that respond to light stimuli for enhanced extraction performance through combined vibrational and optical actuation mechanisms. Photo-responsive scaffold materials can undergo structural changes, mechanical property modifications, or thermal effects when exposed to specific wavelengths of light, providing additional stimuli for moisture extraction beyond purely vibrational actuation. The photo-responsive functionality can enable dual-mode operation where both vibrational energy and optical energy contribute to moisture release from the sorbent material, potentially improving overall extraction efficiency compared to single-stimulusAttorney Docket No. MIT 25345 PCT | 88212-427691 approaches. Photo-responsive scaffolds can incorporate materials such as azobenzene polymers, liquid crystal elastomers, or photoisomerizable compounds that exhibit reversible structural changes upon light exposure.

[0143] Photo-responsive scaffold materials can provide enhanced extraction capabilities by enabling localized heating, structural deformation, or chemical property changes that complement the mechanical effects of vibrational actuation. The optical responsiveness can be tuned to specific wavelengths that enable selective activation of photo-responsive elements while avoiding interference with other system components or environmental factors. Photo-responsive scaffolds can enable spatially selective extraction by directing light to specific regions of the sorbent material where enhanced moisture release is desired, providing additional control over the extraction process beyond what can be achieved through vibrational actuation alone. The combination of photo-responsive and vibrational actuation mechanisms can provide synergistic effects that improve overall system efficiency while enabling more sophisticated control strategies for optimizing moisture extraction under varying environmental conditions.

[0144] The architectured sorbent materials demonstrated in FIGS. 9A-9D can achieve specific resonance frequencies through controlled geometric design and material selection that optimize vibrational energy coupling between the actuator and the moisture-harvesting material. The resonance frequency tuning can be accomplished through adjustment of structural dimensions, material properties, or geometric features that influence the mechanical response characteristics of the sorbent material. The specific resonance frequencies can be matched to the optimal extraction frequencies identified for particular sorbent-water interactions, enabling enhanced extraction efficiency through resonant amplification of vibrational energy. The resonance frequency control can enable system optimization for different environmental conditions, sorbent materials, or actuator configurations while maintaining effective moisture extraction performance across varying operational parameters.

[0145] FIGS. 10A-10B illustrate that the moisture-harvesting material 116 may be fabricated using electrospinning techniques that create nanofibrous structures with controlled fiber diameter, orientation, and porosity characteristics optimized for both moisture capture and vibrational energy transmission. Electrospinning processes can produce continuous nanofibers from hygroscopic polymer solutions through the application of high voltage electric fields that stretch and solidify polymer jets into fiber structures with diametersAttorney Docket No. MIT 25345 PCT | 88212-427691 ranging from tens of nanometers to several micrometers. The electrospinning fabrication method can enable precise control of fiber morphology, surface area, and pore size distribution that can be tailored to optimize moisture adsorption capacity while creating structures that support specific vibrational modes. The electrospun nanofiber configuration provides high surface are a- to- volume ratios that enhance moisture capture efficiency while creating interconnected networks that facilitate vibrational energy propagation throughout the material volume.

[0146] The electrospun nanofiber embodiment 360 can include hygroscopic polymers that provide inherent moisture capture capabilities through hydrophilic functional groups and controlled porosity characteristics. The hygroscopic polymers may include polyacrylamide, polyacrylic acid, polyvinyl alcohol, alginate, cellulose, chitosan, or other water-adsorbing or water-swellable polymers that exhibit strong affinity for water molecules through hydrogen bonding and dipole interactions. The polymer selection can be optimized to achieve desired moisture uptake capacity while maintaining mechanical stability and processability during electrospinning fabrication. The hygroscopic polymer nanofibers can be cross-linked during or after the electrospinning process to enhance mechanical stability and prevent dissolution during moisture extraction cycles while maintaining effective water capture and release characteristics.

[0147] The electrospun nanofiber moisture-harvesting material may be doped with metal-organic frameworks (MOFs) 362 that provide enhanced moisture capture capacity and controlled release characteristics through their crystalline porous structures and tunable surface chemistry. MOF inclusions can be incorporated into the electrospinning solution as suspended particles that become embedded within the polymer nanofibers during the fiber formation process, creating composite structures that combine the high surface area of electrospun fibers with the selective adsorption properties of MOF materials. The MOF doping can enhance moisture uptake at low relative humidity conditions while providing controlled pore sizes and surface functionalities that optimize water binding and release characteristics. The combination of hygroscopic polymer fibers and MOF inclusions can achieve moisture capture performance that exceeds either component individually while maintaining the structural advantages of the nanofibrous architecture. In some embodiments, the MOFs 362 can be embedded in nonwoven sheets 364, as shown in FIG. 10B.

[0148] In some embodiments, the moisture-harvesting material 116 can include a crosslinked hydrogel material that provides controlled swelling behavior, mechanical stability, andAttorney Docket No. MIT 25345 PCT | 88212-427691 tunable water uptake characteristics through chemical or physical crosslinking between polymer chains. Cross-linked hydrogel materials can exhibit three-dimensional network structures where individual polymer chains are connected through covalent bonds, ionic interactions, or physical entanglements that prevent dissolution while allowing controlled water absorption and release. The crosslinking density may be adjusted to optimize the balance between water uptake capacity and mechanical stability, with lower crosslinking densities enabling higher water uptake but potentially reduced mechanical strength, and higher crosslinking densities providing enhanced mechanical stability but potentially limited swelling capacity.

[0149] The mechanical properties of cross-linked hydrogel materials may be characterized by their Young's modulus, which represents the material's resistance to elastic deformation under applied stress. The Young's modulus of hydrogel materials can be significantly increased through controlled particle distribution within the hydrogel matrix. Inorganic particles, polymer microspheres, or other reinforcing fillers distributed throughout the hydrogel network can create composite structures with enhanced mechanical stiffness compared to pure hydrogel materials. The particle distribution may create physical crosslinking points that supplement chemical crosslinks, resulting in increased Young's modulus values that improve the material’s ability to withstand mechanical stresses during vibrational actuation cycles. The enhanced mechanical properties achieved through particle distribution can enable the hydrogel to maintain structural integrity during repeated moisture absorption and extraction processes while preserving effective vibrational energy transmission throughout the material volume.

[0150] The cross-linked hydrogel material may include at least one or a plurality of polymers that provide hydrophilic functionality and controlled swelling behavior suitable for atmospheric water harvesting applications. The polymers may include polyacrylamide, alginic acid, sodium alginate, potassium alginate, ammonium alginate, calcium alginate, propylene glycol alginate, chemically modified alginate, and / or combinations of different alginate types that may provide synergistic properties that optimize both water uptake capacity and mechanical stability for specific operating conditions. In some embodiments, the cross-linked hydrogel material can include polyacrylic acid, hydroxypropyl cellulose, Poly(N-isopropylacrylamide), and / or Poly(N- isopropylacrylamide). In some embodiments, at least one or a plurality of crosslinkers that create chemical bonds between polymer chains to form stable three-dimensional networkAttorney Docket No. MIT 25345 PCT | 88212-427691 structures, such as N,N'-methylenebisacrylamide, one, none, or a plurality of metal salts that enhance water uptake capacity through hygroscopic effects and ionic interactions with water molecules, such as lithium chloride or calcium chloride, thermoresponsive polymers that undergo phase transitions to facilitate liquid water extraction at lower temperatures, and / or ionic liquids. As noted above, the moisture-harvesting material 116 can include hybrid sorbents combining MOFs with hydrogels or thermoresponsive polymers for synergistic performance that exceeds the capabilities of individual components.

[0151] In some embodiments, the moisture-harvesting material 116 can include salt- free hydrogel compositions based on alginate and various monomers without lithium chloride or other metal salts. The salt-free compositions may provide effective moisture capture through polymer hydrophilicity alone while avoiding potential issues associated with salt leaching, corrosion, or environmental contamination. The salt-free hydrogel materials can achieve water uptake capacities approximately in the range of about 0.2 g / g to about 0.6 g / g at 30% relative humidity through optimized polymer composition and crosslinking characteristics. The alginate-based salt-free formulations can combine alginate polymers with monomers such as acrylamide, N-isopropylacrylamide, or acrylic acid in controlled ratios that optimize both water uptake capacity and mechanical stability.

[0152] The salt-free hydrogel compositions can incorporate alginate to monomer ratios approximately ranging from about 10:90 to about 50:50 by weight, enabling optimization of mechanical properties and water uptake characteristics for specific applications. The monomer to crosslinker ratios may approximately range from about 50:1 by weight to about 250:1 by weight, providing control over crosslinking density and resulting swelling behavior. The salt-free formulations may achieve water absorption capacities suitable for atmospheric water harvesting while providing enhanced environmental compatibility and reduced system complexity compared to salt-containing formulations.

[0153] Tn some embodiments, the moisture-harvesting material 1 16 can be fabricated using two-photon polymerization techniques that enable the creation of complex three- dimensional architectures with sub-micrometer resolution and controlled internal structures optimized for vibrational energy manipulation. Two-photon polymerization processes utilize focused laser beams to initiate polymerization reactions in photosensitive materials through nonlinear optical absorption, enabling the fabrication of intricate structures with features smaller than the wavelength of the incident light. The two-photon polymerization approach can create periodic structures, resonant cavities, or other geometric features that trap andAttorney Docket No. MIT 25345 PCT | 88212-427691 amplify specific vibrational modes while maintaining porosity and surface area characteristics required for effective moisture capture. The high-resolution fabrication capability of two-photon polymerization can enable the creation of acoustic metamaterial structures within the moisture-harvesting material that can selectively enhance vibrational energy at frequencies that optimize moisture extraction performance.

[0154] The moisture -harvesting material 116 may be configured to have at least one of a high water uptake capacity, fast vapor capture kinetics, or mechanical stability to withstand an actuation-driven water extraction process performed by the actuator. The high water uptake capacity can enable the moisture-harvesting material 116 to capture substantial quantities of water vapor from the ambient atmosphere, maximizing the amount of moisture available for extraction during vibrational actuation cycles. Water uptake capacity may be measured in grams of water absorbed per gram of dry sorbent material, with effective atmospheric water harvesting materials typically achieving uptake capacities approximately ranging from about 0.2 g / g to over 20 g / g depending on the specific material composition and environmental conditions. The high uptake capacity can enable the system to achieve practical daily water yields while minimizing the mass and volume of sorbent material required for effective operation. A range of vapor capture kinetics that would qualify as being “fast” to fall within the scope of the present disclosure would be understood to be faster than average for a moisture-harvesting material known to one skilled in the art.

[0155] Mechanical oscillation of the actuator 212 can be accompanied by Joule heating caused by the dissipative loss in the material driven at high frequency. The present devices and methods utilize a synergetic impact of the mechanical actuation and device heating to facilitate moisture extraction from sorbents 116, reducing the extraction time relative to the heating-only approach, and increasing the system energy efficiency. Referring to FIG. 11 , for example, the comparative analysis of energy efficiency for moisture extraction methods demonstrates the superior performance of vibrational actuation of the present embodiments compared to conventional thermal extraction approaches. In particular, FIG. 11 presents quantitative data that illustrates the measured rates of water extraction under piezo actuation versus Joule heating at the same steady-state temperature, with calculated energy consumption values for each extraction method. The comparative analysis provides direct evidence of the energy efficiency improvements achieved through vibrational actuation while maintaining comparable or superior moisture extraction rates compared to thermal methods.Attorney Docket No. MIT 25345 PCT | 88212-427691

[0156] In particular, FIG. 11 illustrates the measured rate of water extraction under piezo actuation compared to Joule heating at the same steady-state temperature of the sorbent at 42°C. The piezo actuation method demonstrates significantly lower energy consumption of approximately 7 MJ / kg while achieving an extraction rate of about 75% of the total moisture content within the measurement period. The Joule heating method shows substantially higher energy consumption of approximately 28 MJ / kg while achieving a lower extraction rate of about 35% to about 45%. Referring to FIG. 3C, a configured system using vibrational actuation can achieve moisture extraction performance exceeding that of the thermal limit by at least 45 times.

[0157] The energy consumption comparison presented in FIG. 11 illustrates the fundamental advantage of vibrational actuation over thermal extraction methods by demonstrating that mechanical energy can disrupt water-sorbent interactions more efficiently than thermal energy. The vibrational actuation approach achieves effective moisture release through mechanical disruption of hydrogen bonds and capillary forces without requiring the energy-intensive phase transition from liquid to vapor that characterizes thermal extraction processes. The lower energy consumption of piezo actuation enables the system to operate closer to thermodynamic efficiency limits while maintaining extraction rates that meet practical water production requirements for atmospheric water harvesting applications.

[0158] In some embodiments, the system of the present embodiments may operate in cyclic modes with alternating sorption and desorption periods optimized for maximum daily water yield and energy efficiency. The cyclic operation can enable the atmospheric water harvesting system to continuously capture moisture from the ambient air during sorption periods while extracting the captured water during desorption periods, creating a continuous water production process that maximizes the utilization of both the sorbent material capacity and the available environmental moisture. The alternating cycle approach can allow the system to operate during both daytime and nighttime hours, with sorption periods potentially occurring during high humidity conditions such as nighttime hours when atmospheric moisture content is typically elevated, and desorption periods occurring when energy is available for actuator operation or when environmental conditions favor water collection and storage.

[0159] The cyclic operation mode can enable optimization of both sorption and desoiption phases to achieve maximum daily water yield while maintaining energy efficiency levels that approach theoretical limits. The sorption periods may be extended to allow theAttorney Docket No. MIT 25345 PCT | 88212-427691 moisture-harvesting material to reach near-saturation moisture content, maximizing the amount of water available for extraction during subsequent desorption cycles. The desorption periods may be optimized in duration and intensity to achieve complete or nearcomplete moisture extraction while minimizing energy consumption through efficient utilization of vibrational actuation at optimal frequencies and duty cycles. The alternating cycle approach can enable the system to achieve daily water yields that may exceed what can be accomplished through continuous operation modes while maintaining energy efficiency advantages that make the technology economically viable for practical deployment.

[0160] Referring to FIG. 12, additional frequency performance data can demonstrate the comprehensive relationship between acoustic frequency and energy intensity for moisture extraction from hydrogel materials across an extended frequency spectrum. The energy intensity variations across the frequency spectrum can provide quantitative guidance for actuator selection and system design that can achieve energy consumption levels below the thermal limit threshold while maintaining practical extraction performance for atmospheric water harvesting applications. The frequency performance data can enable system optimization that approaches thermodynamic efficiency limits rather than being constrained by the thermal phase transition requirements that limit conventional heating-based extraction methods. The acoustic frequency advantages demonstrated across multiple optimal frequency ranges can establish vibrational actuation as a transformative technology for atmospheric water harvesting that can achieve energy efficiency levels previously considered impossible for sorption-based moisture extraction systems. The comprehensive frequency characterization provides the technical foundation for developing commercially viable atmospheric water harvesting systems that can address global water scarcity challenges through energy-efficient decentralized water production technologies.

[0161] FIG. 12A, for example, demonstrates results of testing acoustic actuation of microparticle -doped PAM-LiCl hydrogels at audible frequencies to provide more energyefficient moisture extraction compared to conventional thermal methods across a broad range of operating conditions. In particular, for any frequency of the audible sound in the approximate range between about 50 Hz and about 14 kHz, the energy used for extraction can be lower than that in the state-of-the-art AWH systems using thermal extraction (shown as the bar (A)), but higher than the thermal limit (shown as the dashed line (B)).

[0162] Musical compositions that incorporate different frequencies can be optimized to achieve high water extraction, as shown in FIG. 12B. During testing, the acoustic fieldAttorney Docket No. MIT 25345 PCT | 88212-427691 produced by the man-made country, hip-hop (H), disco (D), and reggae (R) genres scored among the highest performers in dewatering, while jazz exhibited the lowest effectiveness. Artificially-generated musical compositions (Al 1st- 15th) that resembled the best-performing songs can provide even better moisture-extraction performance, as shown in FIG. 12B.

[0163] The atmospheric water harvesting system may incorporate artificial intelligence- driven optimization capabilities that utilize machine learning models to predict and control optimal extraction conditions based on environmental parameters and system performance data. The Al-driven optimization enables the system to continuously learn from operational experience and environmental variations to improve extraction efficiency, energy consumption, and daily water yield through adaptive control strategies that respond to changing conditions in real-time. Machine learning models may be trained on historical performance data, environmental measurements, and sorbent material characteristics to develop predictive algorithms that can anticipate optimal operating parameters before environmental changes occur. The Al optimization approach can enable the system to achieve superior performance compared to static control strategies by continuously adapting to environmental variations, sorbent aging effects, and seasonal changes in atmospheric moisture availability.

[0164] The machine learning models may incorporate deep neural networks that provide enhanced pattern recognition capabilities for complex environmental and system state relationships that can influence optimal extraction performance. Deep neural network architectures can include convolutional neural networks for processing spatial environmental data such as weather patterns or atmospheric moisture distribution maps, recurrent neural networks for analyzing temporal sequences of environmental measurements and system performance data, or transformer architectures for capturing long-range dependencies in environmental and operational data. The deep learning approaches can enable the system to identify subtle patterns and correlations in high-dimensional data that may not be detectable through conventional statistical methods or simple machine learning algorithms.

[0165] The system can incorporate sensors and feedback mechanisms that provide comprehensive monitoring capabilities for autonomous optimization of sorption and desorption cycles based on real-time environmental and system state measurements. The sensor array may include environmental sensors for measuring temperature, relative humidity, atmospheric pressure, wind speed, and solar irradiance that influence moisture availability and system energy requirements. System state sensors can monitor actuatorAttorney Docket No. MIT 25345 PCT | 88212-427691 performance, sorbent material properties, energy consumption, water production rates, and component health indicators that affect optimal operational parameters. In some embodiments, the sensors may include impedance sensors that measure electrical resistance or capacitance changes within the moisture-harvesting material as water content varies during extraction cycles, temperature sensors that monitor thermal conditions within the sorbent material to detect heating effects from vibrational actuation or environmental temperature variations that influence extraction performance, and / or strain sensors that measure mechanical deformation of the moisture-harvesting material during vibrational actuation, providing information about material response characteristics and mechanical coupling effectiveness. In some embodiments, an external sensor may utilize microelectromechanical systems (MEMS) devices.

[0166] The sensors may include optical sensors that utilize light transmission, reflection, or absorption measurements to assess moisture content or material properties without direct electrical contact with the moisture-harvesting material. Optical monitoring may provide non-invasive assessment of moisture distribution patterns within the sorbent structure, enabling detection of localized moisture concentrations or extraction progress in different regions of the material. Acoustic sensors may monitor vibrational response characteristics of the moisture-harvesting material during actuation, providing information about mechanical coupling effectiveness and material property changes that influence extraction performance. The sensor array may include multiple sensor types that provide complementary measurement capabilities, enabling comprehensive monitoring of material conditions and extraction progress through multiple measurement modalities.

[0167] The monitoring of transient changes in the moisture-harvesting material may alternatively be performed by the actuator itself through self-sensing capabilities that eliminate the need for separate sensor components. The actuator may function as both a vibrational energy source and a sensing element through impedance monitoring techniques that correlate electrical impedance changes with moisture content variations in the moistureharvesting material. The piezoelectric actuator may exhibit changes in electrical impedance, resonant frequency, or phase angle characteristics as the mechanical properties of the moisture-harvesting material change during moisture extraction. The self-sensing capability enables the actuator to provide continuous feedback about material conditions without requiring additional sensor hardware or electrical connections.Attorney Docket No. MIT 25345 PCT | 88212-427691

[0168] The actuator self-sensing may utilize frequency response analysis that monitors changes in the actuator resonant frequency as the mechanical loading from the moistureharvesting material varies during extraction cycles. The resonant frequency shifts may correlate with moisture content changes, enabling the actuator to provide quantitative feedback about extraction progress based on frequency response measurements. The actuator may monitor phase relationships between applied voltage and resulting current or displacement to assess mechanical coupling effectiveness and material property changes that influence vibrational energy transfer. The self-sensing approach may provide real-time feedback about actuator performance and material conditions while simplifying system design by eliminating separate sensing components and associated electrical connections.

[0169] The feedback mechanisms may incorporate closed-loop control systems that continuously adjust operational parameters based on real-time performance measurements and Al model predictions. The closed-loop control enables the system to respond rapidly to environmental changes or system state variations that affect optimal extraction performance, maintaining high efficiency and water production rates despite dynamic operating conditions. The feedback control may incorporate predictive elements that anticipate future environmental changes based on weather forecasting data or historical patterns, enabling proactive adjustment of operational parameters before environmental changes occur. The predictive feedback enables the system to optimize energy utilization and water production scheduling based on anticipated environmental conditions, improving overall system efficiency and reliability.

[0170] An embodiment of a method of extracting moisture from an atmosphere can include applying at least one of a mechanical vibration or an acoustical vibration to an atmosphere to extract moisture from the atmosphere through non-thermal mechanisms that achieve superior energy efficiency compared to conventional heating-based extraction processes. The method can utilize vibrational energy to disrupt the binding forces between water molecules and sorbent surfaces, enabling moisture release without requiring the energy-intensive phase transitions associated with thermal evaporation-condensation processes. As noted above, the vibrational extraction method can operate across frequency ranges spanning from infrasound frequencies below 20 Hz through audible frequencies from about 20 Hz to about 20 kHz and extending into ultrasonic frequencies from about 20 kHz to about 250 MHz or higher, enabling optimization of extraction performance for different sorbent materials and environmental conditions.Attorney Docket No. MIT 25345 PCT | 88212-427691

[0171] The method may apply mechanical vibrations that generate alternating compression and rarefaction cycles within the moisture-harvesting material, creating mechanical forces that overcome hydrogen bonds and capillary forces that bind water molecules to hydrophilic surface sites. The mechanical vibrations may propagate through the sorbent material as acoustic waves that interact with the microscopic structure of the moisture-harvesting material to promote water release through mechanical disruption rather than thermal energy input. The mechanical vibration application can enable the method to achieve energy consumption levels that approach thermodynamic efficiency limits rather than being constrained by the thermal phase transition requirements that limit conventional extraction approaches.

[0172] The method may alternatively or additionally apply acoustical vibrations that utilize sound energy to facilitate moisture extraction through acoustic coupling mechanisms that transfer vibrational energy from acoustic sources to the moisture-harvesting material. The acoustical vibrations can operate in frequency ranges that optimize acoustic coupling with the mechanical properties of specific sorbent materials, enabling enhanced energy transfer efficiency and improved extraction performance. The acoustical vibration application can utilize conventional audio transduction technologies adapted for moisture extraction applications, providing familiar operational characteristics and established manufacturing processes that can reduce system complexity and cost compared to specialized vibrational actuation approaches.

[0173] The method can incorporate feedback control mechanisms that monitor the effectiveness of different stimulus components during multi-sti muli operation and adjust the relative intensity or timing of each stimulus type to maintain optimal extraction performance. The feedback control may utilize sensors that measure moisture content, extraction rates, energy consumption, or other performance indicators to guide real-time optimization of multi-stimuli parameters. The adaptive multi-stimuli control enables the method to maintain superior extraction efficiency across varying environmental conditions and sorbent material states while accommodating changes in the relative effectiveness of different stimulus mechanisms during operational cycles.

[0174] EXAMPLES

[0175] The methodologies provided for herein offer at least a five-fold reduction, and even forty-five-fold, of the energy needed to extract the same mass of water as the standardAttorney Docket No. MIT 25345 PCT | 88212-427691 evaporation-condensation technique (demonstrated with a Li-PAM hydrogel and a lead zirconate titanate (PZT) ultrasonic actuator in one disclosed embodiment).

[0176] The new moisture extraction techniques, and associated devices and systems, are very general and can be used with other sorbents, including various types of hydrogels, metal organic frameworks (MOFs), superabsorbent fibers and textiles, salts, and / or desiccants. At least because the new technology is not based on heating-induced evaporation, its efficiency is not bound by the thermodynamic limit derived for the conventional desorption process, offering promise for further efficiency improvements. Although the present disclosure is not based on the induction of heat, in at least some embodiments, heat can be used to supplement the disclosed techniques, which are based on vibration and / or acoustics.

[0177] The following examples describe specific aspects of some embodiments of the sorbents that can be utilized with the present disclosure to illustrate and provide a description for those of ordinary skill in the art. The examples should not be construed as limiting the disclosure, as the examples merely provide specific methodology useful in understanding and practicing some embodiments of the present disclosure.

[0178] SORBENT EXAMPLE 1

[0179] A cross-linked PAM-LiCl hydrogel incorporating lithium (Li+) and chloride ions (Cl-). A polyacrylamide hydrogel has been synthesized based on a simple, one-pot approach, where polymer, salt, initiator, crosslinker, and accelerator were all mixed in water. For all hydrogels, about 16.72 g lithium chloride (>99%) salt was dissolved in a beaker with about 50 mL deionized (DI) water. The solution was continuously mixed with a magnetic stirring bar, covered to prevent evaporation, and then left to cool down to room temperature. About 4.18 g of acrylamide (> about 99%) was sequentially added, the N,N’- methylenebisacrylamide (MBA) (about 99%) as crosslinker, and about 14.2 mg of ammonium persulfate (APS) (> about 98%) as initiator. The mixed solution was degassed for about 10 minutes under vacuum in a dessicator. Subsequently, about 12 pL of N,N,N',N'- tetramethylethylendiamin (TEMED) (> about 99%) was added as an accelerator. About 4 mL of solution was poured into a petri dish, covered with the lid, and left to gelate at room temperature overnight. All the chemicals were purchased from Sigma-Aldrich and used as received. The amount of the MBA crosslinker can be varied to control the hydrogelAttorney Docket No. MIT 25345 PCT | 88212-427691 stiffness. In some embodiments, the cross-linker amount can be about 50 mg, about 2.5 mg, or about 0.5 mg.

[0180] SORBENT EXAMPLE 2

[0181] A hydrogel comprising an alginate, and a monomer, and an organic crosslinker, wherein the ratio of alginate to monomer is approximately in the range of about 10:90 to about 50:50 by weight, and wherein the ratio of monomer to organic crosslinker is approximately in the range of from about 50:1 to about 250:1 by weight, and wherein the alginate and polymer formed from monomer and organic crosslinker are covalently crosslinked to form hydrogel network.

[0182] The term "alginate" as used herein refers to a naturally occurring biopolymer derived from brown seaweed, composed primarily of sodium and calcium salts of alginic acid. Alginate can be sourced primarily from brown seaweeds (algae), including species such as Laminaria, Ascophyllum, Macrocystis, Ecklonia, Sargassum, and can be used in this hydrogel composition at least for its water-binding and structural properties.

[0183] The term "monomer" as used herein refers to monomers able to have polymerization initiated by potassium and / or ammonium persulfate in water medium. Suitable monomers include, but are not limited to, acrylamide, N- isopropylacrylamide, acrylic acid, and others. These monomers can be employed to form crosslinked hydrogel network, providing at least flexibility and water absorption capacity.

[0184] The term "organic crosslinker" as used herein refers to a monomer possessing two reactive sites able to have polymerization initiated by potassium and / or ammonium persulfate in water medium. Suitable monomers include, but are not limited to, N,N'- methylenebisacrylamide and others. These monomers can be employed to form crosslinking bridges between polymer chains and alginate, ensuring integrity of hydrogel network during water absorption and / or ultrasound-induced water release.|0185| In some embodiments, the alginate can be selected from the group that includes alginic acid, sodium alginate, potassium alginate, ammonium alginate, calcium alginate, propylene glycol alginate, chemically modified alginate, and combinations thereof. Different types of alginate can include various ratios of a-l-guluronic acid (G) and -d-mannuronic acid (M) residues, linearly linked by 1 ,4-glycosidic linkages in different sequences. ThisAttorney Docket No. MIT 25345 PCT | 88212-427691 variability in structure and functionality may affect the suitability of the alginate for various applications, including its use as a renewable resource in bio-based materials. By allowing the use of different types of alginates, the hydrogel composition can be tailored for various technical needs and regions, utilizing locally available alginate types.

[0186] In some embodiments, the monomer can be selected from the group that includes acrylamide, N-isopropylacrylamide, acrylic acid, and combinations thereof, more preferably acrylamide, N-isopropylacrylamide, combination of acrylamide and acrylic acid in the ratio 2:1 by weight, and combination of acrylamide and N-isopropylacrylamide in the ratio 2:1 by weight.

[0187] In some embodiments, the monomer can be selected from the group that includes acrylamide, N-isopropylacrylamide, acrylic acid, and combinations thereof, more preferably acrylamide, combination of acrylamide and acrylic acid in the ratio 2:1 by weight, and combination of acrylamide and N-isopropylacrylamide in the ratio 2:1 by weight.

[0188] In some embodiments, a selected organic crosslinker can be N,N'- methylenebisacrylamide.

[0189] In some embodiments, the ratio of alginate to monomer can be approximately in the range of from about 10:90 to about 50:50, or approximately in the range of from about 20:80 to about 30:70 by weight. These specific ratios of alginate to monomer balance water absorption capacity and mechanical stability, providing a durable hydrogel that can withstand water absorption and release cycles without losing integrity.

[0190] In some embodiments, the ratio of monomer to organic crosslinker can be approximately in the range of about 50: 1 to about 250: 1, or approximately in the range of from about 100:1 to about 150:1 by weight. The precise control of the crosslinking agent concentration can allow for a hydrogel with balanced water absorption capacity.

[0191] In some embodiments, additional crosslinking can be ensured by immersion of hydrogel samples into calcium chloride water solution with concentration approximately in the range from about 0.2 wt% to about 35 wt%. Calcium ions provide additional crosslinking of hydrogel network through an ionic gelation process, where calcium ions interact with the guluronic acid (G) blocks in the alginate polymer chains and enhance water adsorption capacity.Attorney Docket No. MIT 25345 PCT | 88212-427691

[0192] In some embodiments, the hydrogel composition has a water absorption capacity approximately in the range of about 0.2 g / g to about 0.6 g / g at humidity of about 30%.

[0193] Example 2.1; Preparation of Hydrogel based on Alginate andAcrylamide. Alginic acid sodium salt, acrylamide, N,N'-methylenebisacrylamide, and ammonium persulfate were supplied by Sigma- Aldrich and used as received. In an approximately 250 mL reaction vessel, about 5 g of alginate was dissolved in about 200 mL of deionized water. The mixture was stirred at about 500 rpm for about 12 hours to ensure complete dissolution. Subsequently, about 22 g of acrylamide and about 0.185 g of N,N'- methylenebisacrylamide were added to the reaction mixture under continuous stirring. The total concentration of reagents was maintained at about 15 wt%. The reaction mixture was stirred for an additional approximately 30 minutes and then purged with nitrogen for approximately 60 minutes. Subsequently, the composition was heated to about 80 °C for about 2 hours. Upon completion, the resulting hydrogel was washed with deionized water for about 10 hours to remove unreacted monomers and freeze-dried for about 24 hours. The final product, denoted as Alg / AAm / MBA6, was subjected to further characterization.

[0194] Example 2.2; Preparation of Hydrogel based on Alginate and Acrylamide with Ca2 ing. Alginic acid sodium salt, acrylamide, N,N’- methylenebisacrylamide, calcium chloride, and ammonium persulfate were supplied by Sigma-Aldrich and used as received. In an approximately 250 mL reaction vessel, about 5 g of alginate was dissolved in about 200 mL of deionized water. The mixture was stirred at about 500 rpm for about 12 hours to ensure complete dissolution. Subsequently, about 22 g of acrylamide and about 0.185 g of N,N'-methylenebisacrylamide were added to the reaction mixture under continuous stirring. The total concentration of reagents was maintained at about 12 wt%. The reaction mixture was stirred for an additional approximately 30 minutes and then purged with nitrogen for approximately 60 minutes. Subsequently, the composition was heated to about 80 °C for about 2 hours. After cooling down, hydrogel was cut into pieces and immersed in a calcium chloride solution of about 35 wt% for about 1 hour. Upon completion, the resulting hydrogel was washed with deionized water for about 10 hours to remove unreacted monomers and freeze-dried for about 24 hours. The final product, denoted as Alg / AAm / MBA6 / Ca2+, was subjected to further characterization.Attorney Docket No. MIT 25345 PCT | 88212-427691

[0195] Example 2.3; Preparation of Hydrogel based on Alginate and N- isopropylacrvlamide. Alginic acid sodium salt, N-isopropylacrylamide, N,N'- methylenebisacrylamide, and ammonium persulfate were supplied by Sigma-Aldrich and used as received. In an approximately 250 mL reaction vessel, about 5 g of alginate was dissolved in about 200 mL of deionized water. The mixture was stirred at about 500 rpm for about 12 hours to ensure complete dissolution. Subsequently, about 34 g of N- isopropylacrylamide and about 0.185 g of N,N'-methylenebisacrylamide were added to the reaction mixture under continuous stirring. The total concentration of reagents was maintained at about 12 wt%. The reaction mixture was stirred for an additional approximately 30 minutes and then purged with nitrogen for approximately 60 minutes. Subsequently, composition was heated to about 80 °C for about 2 hours. Upon completion, the resulting hydrogel was washed with deionized water for about 10 hours to remove unreacted monomers and freeze-dried for about 24 hours. The final product, denoted as Alg / NiPAAm / MBA6, was subjected to further characterization.

[0016] Example 2.4; Preparation of Hydrogel based on Alginate, Acrylamide and ic Acid Alginic acid sodium salt, acrylamide, N,N'-methylenebisacrylamide, and ammonium persulfate were supplied by Sigma- Aldrich and used as received. Acrylic acid was obtained from Sigma-Aldrich and purified with activated carbon before utilization. In an approximately 250 mL reaction vessel, about 5 g of alginate was dissolved in about 200 mL of deionized water. The mixture was stirred at about 500 rpm for about 12 hours to ensure complete dissolution. Subsequently, about 22 g of acrylamide and about 0.185 g of N,N'- methylenebisacrylamide were added to the reaction mixture under continuous stirring. The total concentration of reagents was maintained at about 10 wt%. The reaction mixture was stirred for an additional approximately 30 minutes and then purged with nitrogen for approximately 60 minutes. Subsequently, the composition was heated to about 80 °C for about 2 hours. Upon completion, the resulting hydrogel was washed with deionized water for about 10 hours to remove unreacted monomers and freeze-dried for about 24 hours. The final product, denoted as Alg / AAm / AAc / MBA6, was subjected to further characterization.

[0197] METHODS

[0198] Hydrogel synthesis

[0199] Polyacrylamide hydrogels were synthesized based on a simple, one-pot approach, where polymer, salt, initiator, crosslinker, and accelerator, were all mixed in water. For allAttorney Docket No. MIT 25345 PCT | 88212-427691 hydrogels, we first dissolved the 16.72 g lithium chloride (>99%) salt in a beaker with 50 mL deionized (DI) water. The solution was continuously mixed with a magnetic stirring bar, covered to prevent evaporation, and then left to cool down to room temperature. 4. 18 g of acrylamide (>99%) was added, the N,N’-methylenebisacrylamide (MBA) (99%) as crosslinker (50 mg for HG-C, 2.5 mg for HG-B and 0.5 mg for the HG-A) and 14.2 mg of ammonium persulfate (APS) (>98%) as initiator. The mixed solution was degassed for 10 minutes under vacuum in a dessicator. Finally, we added 12 pL of N,N,N',N'- tetramethylethylendiamin (TEMED) (>99%) as accelerator. 4 mL of solution were poured into a petri dish, covered with the lid, and left to gelate at room temperature overnight. All the chemicals were purchased from Sigma-Aldrich and used as received.

[0200] Sorption evaluation

[0201] The dynamic vapor sorption isotherms were characterized using an environmental simulation chamber (BINDER GmbH). Initially, the samples were dried at a temperature of 95°C, for a duration of 24 hours using a gravity convection oven (MTI Corporation). Subsequently, the weight of the samples that had been dried in the oven was measured using an analytical balance (OHAUS Corporation). Next, the oven-dried samples were treated inside the environmental chamber under varying RHs (15%, 30%, 55%, 85%) at a constant 25°C temperature and at a maximum stage time of 720 min, ensuring that the specimen weight reached an equilibrium state. In addition to the designed hydrogel, a commercially available hydrogel (HG-M) (a cross-linked glycerol- 2-Acrylamido-2-methylpropanesulfonic acid sodium salt hydrogel, Medela) was used. Finally, the water uptake was quantified by calculating the ratio of the water content in the sample at equilibrium to its oven-dried weight. The findings are shown as the mean ± standard deviation.

[0202] Oscillatory shear rheology characterization

[0203] Rheological experiments were conducted using a rheometer (HR- 20, TA Instruments). For all the experiments, a 25mm parallel plate geometry was employed to ensure accurate loading on the hydrogel specimens. A circular mold was used to fabricate gelled discs, which were formed into a diameter of 25 mm for utilization underneath the parallel plate. Before conducting the tests, the samples were given a five-minute period to reach a state of equilibrium, ensuring that both mechanical and thermal factors were balanced. The temperature was controlled using a built-in Peltier system. The experiments involving the oscillatory frequency and strain / amplitude sweeps were carried out at 25°C.Attorney Docket No. MIT 25345 PCT | 88212-427691Temperature sweep experiments were conducted at an angular frequency of 6.28 rad / s and 0.1% strain.

[0204] Thermal analysis

[0205] Thermogravimetric analysis was conducted to evaluate the desorption behavior and thermal stability of the hydrogels using a thermal analysis system (TGA 5500, TA Instruments). Approximately 10 mg of samples were put into a titanium pan in the presence of nitrogen gas and were heated gradually at a rate of l°C / min until they reached a temperature of 50°C.

[0206] Surface morphology

[0207] The surface morphology of the hydrogel specimens was examined using a scanning electron microscope (SEM) (Zeiss Sigma 300 VP). Hydrogels were completely dehydrated to prevent off-gassing during sputtering and SEM imaging. To prepare the samples and visualize them under the SEM, they were stuck to aluminum stubs with doublesided carbon tape. Next, a sputter coater (Desk V, Denton) was used to apply a 10 nm thin film coating of gold / palladium (Au / Pd) (60:40) in presence of argon gas.

[0208] Piezoelectric ultrasonic device architecture

[0209] The solid housing for the piezoelectric transducer was modelled in SOLIDWORKS and parts were printed using a Bambu Lab Xl-Carbon Combo 3D printer. Aside from the glass domes, all parts within the assembly have a hole with a 12 mm diameter in the center to allow droplets to fall into the bottom dome since water can be harvested from the hydrogel on both sides (top and bottom) of the piezoelectric transducer. Two-ring structures, top and bottom insulators, are used to hold two glass domes in place. Cuts are made into the assembly to allow the domes to slide into the case. The top insulator is 8 mm tall, has an outer diameter of 33 mm, and an inner diameter of 25mm, allowing for a perfect fit of the glass dome, which had an outer diameter of slightly below 25mm. The wire track that houses the piezoelectric device is 8 mm tall and has an outer diameter of 20 mm and an inner diameter of 17 mm. Also, it has a cut that is 2 mm deep to hold the piezoelectric ring and provides a cavity to allow wiring and ambient moisture access into the case. The support platform connects the top and bottom insulators. The bottom insulator and the tripod together host the bottom glass dome. Each leg of the tripod is 38 mm long.

[0210] The piezoelectric transducer was circular in shape, where a piezoelectric ring made of lead zirconate titanate (PZT) polycrystal was affixed to a porous stainless-steelAttorney Docket No. MIT 25345 PCT | 88212-427691 membrane. To fabricate the transducer for our system, the membrane and the PZT rings were purchased from Dongguan Norvis Electronic Corporation and securely fastened. The PZT was affixed to the porous membrane by clamping one side, while the other side was covered with a hydrophobic epoxy resin. Porous membranes with three different nozzle sizes (10, 70, and 100 pm) were used with PZT crystals of two different frequencies to build the low (-110 kHz) and high (-165 kHz) frequency actuators. Piezo drivers were used to actuate the transducer at two different duty cycles of 70+3% and 30+3%, operating at RMS voltages of 40 and 30 V, respectively. The driver boards were powered at 1 .5 W using a DC power supply to drive the piezoelectric transducers.

[0211] Piezoelectric charge coefficient do measurement of the piezoelectric materials

[0212] A Berlincourt meter was employed to measure the piezoelectric coefficients, dss (pC / N), of the PZT crystals used in fabricating the four transducers. During the measurement of the coefficients, both a static force and a dynamic force are exerted on the sample. The tool controls and maintains a constant dynamic force of 0.25N / 110Hz, while the static force of around - IN was manually controlled. The static force is measured using a static force sensor to assure consistent.

[0213] Electrical impedance, resonant spectra, and electromechanical coefficients of piezo transducers

[0214] The electrical phase-impedance spectrum of the transducer devices was measured using an impedance spectroscopy (Solartron SI 1260, AMETEK). The impedance spectrum was screened to obtain two key parameters, the anti-resonance (fa) and resonance (fr) frequencies. The evaluation of the effectiveness of piezoelectric devices in converting electric energy into mechanical energy was conducted based on their effective electromechanical coupling coefficient (keff) using the following equation: keff — ^fa2~fr2 / fa2-

[0215] Elemental mapping, surface roughness imaging, and atomization photography

[0216] Elemental mapping, surface roughness imaging, and atomization photography Zeiss Sigma 300 VP was used to capture SEM images of the membrane nozzles and PZT material. The tool also employed Energy Dispersive X-ray (EDX) technology for elemental mapping of the PZT devices and provides precise information about their composition. AAttorney Docket No. MIT 25345 PCT | 88212-427691 laser scanning confocal microscope (VK-X250, Keyence) was used to do non-contact surface profiling and roughness assessment of the membrane after the extraction cycle. The Nikon D53OO DSLR camera was used to capture the atomization process of water as it was expelled from the hydrogel and funneled through the nozzles of the porous membrane incorporated into the transducer. A green crossline was generated using a 520 nm green laser module (OXLasers), with the focal point positioned below the nozzle axis. This improved the process of envisioning for photography. T-slotted aluminum extrusions were used to build a platform for mounting the transducer between two L-shaped joint brackets to perform imaging experiments.

[0217] Infrared imaging

[0218] To monitor and visualize hydrogel heating caused by the PZT transducer heat generation, an infrared (IR) thermal camera (FLIR ETS32O, Teledyne FLIR LLC) was utilized. IR imaging was also used to monitor the process of hydrogel cooling to ambient temperature after the actuation process. Due to the challenge of IR-imaging a highly polished surface such as a metallic stainless-steel membrane in our device, Dr. Scholl's™ spray was used to deposit a thick opaque layer onto the membrane, and during imaging, emissivity (e) value of 0.95 was set in the IR camera.

[0219] Ultrasonic radiation sensitivity

[0220] An acoustic sensor hydrophone (H Instruments) to measure and quantify the force exerted by a piezoelectric transducer as a function of voltage (V). To conduct the acoustic experiment, the transducer was placed within a petri dish and the hydrogel samples were attached to the device. The acoustic sensor was linked to its amplifier board operating at 9V that had a gain of 25 dB with bandwidth up to 120kHz and placed on the hydrogel surface. The transmitted and received waveforms were recorded. The device served as the transmitter, while the acoustic sensor functioned as the receiver. The resulting output voltage was measured for hydrogel samples of varying thickness.

[0221] Comparative weight-loss study between Joule heater membrane and the transducer

[0222] A multi-channel calibrated commercial K-type thermocouple (HT-9815, RISE PRO) was used to measure the temperature of a free-standing (i.e. , not clamped to the PZT) stainless steel membrane used as the Joule heater. The transducer device received a power supply of 1.5 W in order to maintain a consistent temperature for a comparative analysis.Attorney Docket No. MIT 25345 PCT | 88212-427691Throughout the experiment, either Joule heating or ultrasonic actuation were applied for 1 minute each, followed by a subsequent short deactivation period to weigh the amount of weight loss. The weight loss (%) of the hydrogel was calculated by comparing the extracted mass to the initial mass of the sample.

[0223] Vibrational spectra of wetted hydrogels

[0224] Fourier transform infrared (FTIR) spectroscopy was used to investigate the changes in the vibrational spectra of hydrogels with different level of cross-linking and varying moisture content. FTIR with a built-in attenuated total internal reflectance (ATR) capability was used (iS50, ThermoFisher). The raw FITR spectra were deconvoluted into distinct Gaussian peaks corresponding to individual vibrational modes of polymer and trapped water molecules.

[0225] Energy consumption and efficiency calculation

[0226] The energy consumption, E [MJ / kg], required for moisture extraction was calculated as follows: E = P / m =((power, kWh) ■ duty cycle, %) ■ 3.6 ■ 106input energy [MJ], and m [kg] is the extracted mass. Using the energy consumption (E), the efficiency of the water release process of our device, r], is calculated as p = hiv / E, where hlv= 2.257 [MJ / kg] is the enthalpy of vaporization of water.

[0227]

[0228] 3D electromechanical finite element modeling (FEM)

[0229] COMSOL Multiphysics® was used to simulate vibrational modes of the transducer device consisting of a PZT ring clamped to a steel membrane with nozzles. Solid Mechanics and Electrostatics modules were used to study the deformation dynamics, and a 3D asymmetrical model was constructed to facilitate visualization. Using a voltage sweep, the displacement and velocity were studied, and the phase-impedance spectrum was analyzed employing a frequency sweep. Simulating the nozzle dispersion pattern akin to the manufactured membrane proved challenging in COMSOL. Consequently, all the nozzles were uniformly distributed and a diameter of 50 pm was used to accommodate around 800 nozzles. The simulation results for impedance, velocity, and displacement exhibited a high degree of agreement with the experimental data, without significant deviation. This simulation technique was also employed to visualize the behavior of ultrasonic radiation inAttorney Docket No. MIT 25345 PCT | 88212-427691 hydrogel. For this study purpose, the Young's modulus (E) was determined from the storage modulus of our hydrogel utilizing the formula E = 2G(1 + p), where p represents the Poisson ratio and storage modulus was used as the magnitude for G. The density was estimated at approximately 1200 kg / m3according to literature, and a Poisson's ratio of 0.5 is often employed for hydrogels. Following the calculation, the inputs were entered into COMSOL to simulate the sound pressure induced by the actuator in the hydrogel volume.

[0230] Deep neural network for the extraction dynamics monitoring

[0231] Edge Impulse machine learning platform was used to build a deep neural network, which was used to categorize and distinguish between different types of hydrogels during the sorption process. The neural network was trained using the measured dynamic changes in the phase angle and impedance of the transducer loaded with hydrogel samples, which were continuously sorbing moisture at -20% RH and ~19°C. The trained model has three hidden layers, with a total of 100 neurons, and exhibited accuracy of 100%. The training phase used 77% of the datasets, while the remaining 23% were allocated for testing the model.

[0232] Examples of the above-described embodiments can include the following:1. A system for atmospheric water extraction, comprising: an actuator configured to produce at least one of mechanical vibrations, acoustical vibrations, magnetic stimuli, or electromagnetic stimuli; an electrical circuit in electrical communication with the actuator that is configured to drive the actuator with one or more of pre-designed frequencies, amplitudes, or duty cycle: and a moisture-harvesting material disposed in contact with the actuator.2. The system of example 1, further comprising: at least one of a mesh or a membrane, the at least one of a mesh or a membrane having zero or multiple perforations or nozzles, wherein, optionally, the at least one of a mesh or a membrane is configured to operate as an electrode for at least one of the actuator or the electrical circuit.3. The system of example 1 or example 2, further comprising: a scaffold integrated within the moisture-harvesting material, the scaffold being configured to serve as a transducer of vibrational modes.Attorney Docket No. MIT 25345 PCT | 88212-4276914. The system of example 3, wherein the scaffold comprises at least one of a 3D printed structure, a wire grid, a plurality of nano- or micro-particles, a knitted or woven textile, a non-woven structure, or a plurality of fibers, yams, braids, or rods.5. The system of any of examples 1 to 4, further comprising: an in-situ sensor configured to monitor transient changes in properties of the moisture-harvesting material and provide feedback to at least one of the actuator or the electrical circuit in view of the monitored transient changes in properties.6. The system of any of examples 1 to 5, further comprising a droplet collector to guide water extracted by the actuator.7. The system of any of examples 1 to 6, further comprising an enclosure to collect water extracted by the actuator.8. The system of any of examples 1 to 7, further comprising a mechanical support structure to which the actuator is configured to mount or into which the actuator is integrated.9. The system of any of examples 1 to 8, wherein the actuator comprises at least one of piezoelectric films, piezoelectric scaffolds, a piezoelectric element, or fiber-based scaffolds.10. The system of example 9, wherein the piezoelectric element comprises at least one of inorganic piezoelectric materials, including but not limited to lead zirconate titanate (PZT), barium titanate, zinc oxide, or lithium niobate.11. The system of example 10, wherein the piezoelectric films or fiber-based scaffolds comprise polymer piezoelectric materials, including but not limited to polyvinylidene fluoride (PVDF), polyvinylidene fluoridetrifluoroethylene (PVDF-TrFE) copolymer, poly-1- lactic acid (PLLA), polyacrylonitrile (PAN), nylon, or silk.12. The system of any of examples 9 to 11, wherein the piezoelectric scaffold comprises at least one of polymer materials with inorganic micro- or nano-scale fillers or polymer materials without inorganic micro- or nano-scale fillers.13. The system of any of examples 1 to 12, wherein the moisture-harvesting material comprises one or more of a hydrogel with inorganic micro- or nano-scale fillers or without inorganic micro- or nano-scale fillers, a metal organic framework (MOF), a hygroscopicAttorney Docket No. MIT 25345 PCT | 88212-427691 fibrous material with or without embedded MOF inclusions, a polymer matrix with or without pores, or a hydroscopic salt.14. The system of any of examples 1 to 13, wherein the actuator comprises one or more of an acoustic speaker, an ultrasonic actuator, a microwave source, or an electromagnetic wave antenna.15. The system of any of examples 1 to 14, wherein the electrical circuit comprises at least one of: an electric input signal waveform, a mechanism to adjust the driving frequency, or a method to boost or amplify the input voltage through the use of at least one of a booster, a transformer, or an amplifier.16. The system of any of examples 1 to 15, wherein the actuator is configured to dynamically monitor the moisture-harvesting material and provide feedback to the electrical circuit.17. The system of example 16, further comprising one or more additional sensors configured to dynamically monitor a moisture content of the moisture-harvesting material and provide feedback to at least one of the actuator or the electrical circuit in view of the same.18. The system of any of examples 1 to 17, wherein the moisture-harvesting material is configured to have at least one of a high water uptake capacity, fast vapor capture kinetics, or mechanical stability to withstand an actuation-driven water extraction process performed by the actuator.19. The system of any of examples 1 to 18, wherein the moisture-harvesting material comprises a cross-linked hydrogel material.20. The system of example 19, wherein the cross-linked hydrogel material comprises at least one of polyacrylamide, alginate (alginic acid, sodium alginate, potassium alginate, ammonium alginate, calcium alginate, propylene glycol alginate, chemically modified alginate, and combinations thereof), polyacrylic acid, hydroxypropyl cellulose, or Poly(N- isopropylacrylamide).Attorney Docket No. MIT 25345 PCT | 88212-42769121. The system of example 19 or example 20, wherein the cross-linked hydrogel material comprises one, none, or a plurality of lithium chloride, calcium chloride, or magnesium chloride.22. The system of any of examples 1 to 21, wherein the moisture-harvesting material is configured to serve as at least one of a vibrational signal resonator or amplifier.23. The system of any of examples 1 to 22, wherein the moisture-harvesting material encapsulates a scaffold that provides mechanical stability and serves as a transducer for vibrational modes propagation through a volume of the moisture-harvesting material.24. The system of any of examples 1 to 23, wherein the moisture-harvesting material encapsulates an active scaffold that is configured to serve as the actuator, or as an additional actuator.25. The system of example 24, wherein the active scaffold comprises at least one of a knitted or woven textile, a non-woven structure, or a plurality of fibers, yarns, braids, films, bars, or rods.26. A method of extracting moisture from an atmosphere, comprising: applying at least one non-thermal stimulus to a moisture-harvesting material to extract moisture from the moisture-harvesting material, the moisture harvesting material having captured the moisture from the atmosphere.27. The method of example 26, wherein the non-thermal stimulus comprises one or more of a mechanical vibration, an acoustical vibration, a microwave stimulus, or a magnetic stimulus.28. The method of example 26 or example 27, wherein applying at least one non-thermal stimulus to the moisture-harvesting material further comprises: driving the applying action by way of an electrical circuit using at least one of predesigned frequencies, amplitudes, or duty cycles.29. The method of any of examples 26 to 28, wherein the moisture-harvesting material is disposed in contact with an actuator that applies the at least one non-thermal stimulus.Attorney Docket No. MIT 25345 PCT | 88212-42769130. The method of example 29, further comprising: monitoring transient changes in the moisture-harvesting material using one or more sensors; and providing feedback to at least one of the actuator or an electrical circuit in electrical communication with the actuator, the electrical circuit driving the actuator.31. The method of example 30, wherein monitoring transient changes in the moistureharvesting material is performed by the actuator.32. The method of any of examples 29 to 31, wherein the moisture-harvesting material operates as at least one of a vibrational signal resonator or an actuator.33. The method of any of examples 29 to 32, wherein the moisture-harvesting material encapsulates an active scaffold and performs the action of applying at least one of a mechanical vibration or an acoustical vibration to an atmosphere to extract moisture from the atmosphere.34. The method of any of examples 27 to 33, operating a mechanical scaffold as a transducer to supply the mechanical vibration.35. The method of any of examples 27 to 34, further comprising guiding the extracted moisture.36. The method of any of examples 27 to 35, further comprising collecting the extracted moisture

[0233] Although the procedures provided for herein are described in conjunction with performing atmospheric water extraction using vibrational and / or acoustic actuation, the instruments and procedures provided for herein can also be used and applied in dehumidification systems, industrial drying processes, water recovery from waste streams, and other moisture extraction applications where energy efficiency is critical. A person skilled in the art, in view of the present disclosures, will understand how the dehumidification systems, industrial drying processes, water recovery from waste streams, and other moisture extraction applications can be implemented in view of the present disclosures.

[0234] One skilled in the art will appreciate further features and advantages of the disclosure based on the above-described embodiments. Accordingly, the disclosure is not toAttorney Docket No. MIT 25345 PCT | 88212-427691 be limited by what has been particularly shown and described, except as indicated by the appended claims. By way of example, the vibrational and acoustic actuation methods disclosed herein can be adapted for use with different types of sorbent materials beyond hydrogels, including metal-organic frameworks, hygroscopic salts, and fibrous materials, and can be implemented at various scales from portable personal devices to larger industrial water production systems. A person skilled in the art, in view of the present disclosures, will be able to adapt some or all of the various systems, devices, and methods disclosed herein for applications in dehumidification systems, industrial drying processes, water recovery from waste streams, and other moisture extraction applications where energy efficiency is critical. All publications and references cited herein are expressly incorporated herein by reference in their entirety.

Claims

Attorney Docket No. MIT 25345 PCT | 88212-427691CLAIMSWhat is claimed is:

1. A system for atmospheric water extraction, comprising: an actuator configured to produce at least one of mechanical vibrations, acoustical vibrations, magnetic stimuli, or electromagnetic stimuli; an electrical circuit in electrical communication with the actuator that is configured to drive the actuator with one or more of pre-designed frequencies, amplitudes, or duty cycle; and a moisture-harvesting material disposed in contact with the actuator.

2. The system of claim 1, further comprising: a scaffold integrated within the moisture-harvesting material, the scaffold being configured to serve as a transducer of vibrational modes.

3. The system of claim 2, wherein the scaffold comprises at least one of a 3D printed structure, a wire grid, a plurality of nano- or micro-particles, a knitted or woven textile, a non-woven structure, or a plurality of fibers, yams, braids, or rods.

4. The system of claim 1, further comprising: an in-situ sensor configured to monitor transient changes in properties of the moisture-harvesting material and provide feedback to at least one of the actuator or the electrical circuit in view of the monitored transient changes in properties.

5. The system of claim 1, further comprising a mechanical support structure to which the actuator is configured to mount or into which the actuator is integrated.

6. The system of claim 1, wherein the actuator comprises at least one of piezoelectric films, piezoelectric scaffolds, a piezoelectric element, or fiber-based scaffolds.

7. The system of claim 6, wherein the piezoelectric element comprises at least one of inorganic piezoelectric materials, including but not limited to lead zirconate titanate (PZT), barium titanate, zinc oxide, or lithium niobate.

8. The system of claim 7, wherein the piezoelectric films or fiber-based scaffolds comprise polymer piezoelectric materials, including but not limited to polyvinylideneAttorney Docket No. MIT 25345 PCT | 88212-427691 fluoride (PVDF), polyvinylidene fluoridetrifluoroethylene (PVDF-TrFE) copolymer, poly-1- lactic acid (PLLA), polyacrylonitrile (PAN), nylon, or silk.

9. The system of claim 1, wherein the moisture-harvesting material comprises one or more of a hydrogel with inorganic micro- or nano-scale fillers or without inorganic micro- or nano-scale fillers, a metal organic framework (MOF), a hygroscopic fibrous material with or without embedded MOF inclusions, a polymer matrix with or without pores, or a hydroscopic salt.

10. The system of claim 1, wherein the actuator comprises one or more of an acoustic speaker, an ultrasonic actuator, a microwave source, or an electromagnetic wave antenna.

11. The system of claim 1, wherein the actuator is configured to dynamically monitor the moisture-harvesting material and provide feedback to the electrical circuit.

12. The system of claim 11, further comprising one or more additional sensors configured to dynamically monitor a moisture content of the moisture-harvesting material and provide feedback to at least one of the actuator or the electrical circuit in view of the same.

13. The system of claim 1, wherein the moisture-harvesting material encapsulates an active scaffold that is configured to serve as the actuator, or as an additional actuator.

14. The system of claim 13, wherein the active scaffold comprises at least one of a knitted or woven textile, a non-woven structure, or a plurality of fibers, yams, braids, films, bars, or rods.

15. A method of extracting moisture from an atmosphere, comprising: applying at least one non-thermal stimulus to a moisture-harvesting material to extract moisture from the moisture -harvesting material, the moisture harvesting material having captured the moisture from the atmosphere.

16. The method of claim 15, wherein the non-thermal stimulus comprises one or more of a mechanical vibration, an acoustical vibration, a microwave stimulus, or a magnetic stimulus.

17. The method of claim 15, wherein applying at least one non-thermal stimulus to the moisture-harvesting material further comprises:Attorney Docket No. MIT 25345 PCT | 88212-427691 driving the applying action by way of an electrical circuit using at least one of predesigned frequencies, amplitudes, or duty cycles.

18. The method of claim 15, wherein the moisture -harvesting material is disposed in contact with an actuator that applies the at least one non-thermal stimulus.

19. The method of claim 18, further comprising: monitoring transient changes in the moisture-harvesting material using one or more sensors; and providing feedback to at least one of the actuator or an electrical circuit in electrical communication with the actuator, the electrical circuit driving the actuator.

20. The method of claim 18, wherein the moisture-harvesting material encapsulates an active scaffold and performs the action of applying at least one of a mechanical vibration or an acoustical vibration to an atmosphere to extract moisture from the atmosphere.

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