Thermally insulating compositions and methods

Abstract

A method of preparing a thermoregulating composition is disclosed. The method includes the generation of microparticles from dried Lunaria septa and the use of this composition in thermoregulating products is described.

Description

THERMALLY INSULATING COMPOSITIONS AND METHODSCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is related to and claims priority to United States Provisional Patent Application Serial Number 63 / 617,298, filed January 3, 2024, which is incorporated by reference herein in its entirety for all purposes.STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH

[0002] Not applicable.REFERENCE TO A SEQUENCE LISTING

[0003] Not applicable.FIELD OF THE INVENTION

[0004] The disclosed technology is generally directed to compositions that are designed to provide passive thermal insulation. More particularly the technology is directed to novel compositions including biodegradable microparticles exhibiting thermoregulating properties. The disclosed technology is also related to articles and materials coated with one or more Lunaria septa. The disclosed technology is also related to articles and materials coated with compositions that are designed to provide passive thermal insulation.BACKGROUND

[0005] Passive cooling offers the potential to cool objects below the surrounding ambient temperature during the daytime without requiring energy input. This holds great promise for significant energy conservation and reduction in CO2 emissions. However, up to this point, most cooling surfaces have been created through energy-intensive nanofabrication methods or have relied on unsustainable materials or solvents. To achieve effective radiative cooling, the optical properties of materials can be manipulated in two ways: (i) reduce their absorption of sunlight and atmospheric thermal radiation and (ii) enhance their ability to emit radiation within the atmospheric transparency window. Materials with these relevant properties have been developed through nano- and micro- structured technologies and surface engineering. Some noteworthy designs include microsphere-based photonic random media, thin- film multi-layer structures, microsphere-periodic arrays, metal-dielectric nanophotonic structures, double-layer nanoparticle- based coatings, aerogels, porous synthetic polymer-based coatings, and hybrid dielectric -polymer materials. However, several of these technologies necessitate complex engineering and fabrication processes, which hinder their large-scale production and practical application. Lab-based passive thermal coatings have been fabricated using cellulose derivatives such as nanocrystals which implies the use of strong sulfuric acid for the crystals isolation process and a self-assembly step under specific lab conditions. Other processes described the fabrication of cooling materials using non-degradable synthetic polymers.

[0006] Ideally, sustainable materials should be used to create coatings that represent a viable cooling technology, avoiding the use of plastics or heavy metals to ensure a meaningful positive impact on the environment, result in substantial global energy savings, and contribute to climate change mitigation.SUMMARY

[0007] In an aspect, a method of preparing a thermoregulating composition is disclosed. The method comprises the step of submerging dried Lunaria septa in a thermal bath at a temperature of below -10 °C, below -50 °C, below - 100 °C, below -150 °C, below -195 °C or in liquid nitrogen for at least 10 seconds, at least 30 seconds, at least 1 minute, at least 2 minutes, at least 2 minutes 30 seconds, or at least 3 minutes. The method further comprises the step of fragmenting dried Lunaria septa to microparticles while maintaining a temperature of the dried Lunaria septa below 15 °C. The method further comprises the step of fractionating the microparticles. The submerging, fragmenting, and / or fractionating are adapted to provide desired thermoregulating properties.

[0008] In an aspect, a thermoregulating composition is disclosed herein, wherein the thermoregulating composition comprises fragmented and fractionated dried Lunaria septa, wherein the dried Lunaria septa possess a porosity that is at least 40%, at least 50%, at least 60%, at least 70%, at least 80%, or at least 90%.

[0009] In another aspect, a method of using cellulose microparticles for thermoregulation is disclosed wherein the method comprises producing cellulose microparticles from Lunaria septa, wherein the Lunaria septa possess a porosity that is at least 40%, at least 50%, at least 60%, at least 70%, at least 80%, or at least 90%, combining the cellulose microparticles with at least one carrier at or above 1 wt% particle concentration to generate a formulation, and applying the formulation to a material to provide thermoregulation, wherein the microparticles are between 10 pm and 1000 pm in diameter.

[0010] In another aspect, a thermoregulating composition is disclosed, the thermoregulating composition comprising a particle comprising greater than 50% cellulose, wherein the particle comprises an array of parallel-arranged cellulose tubes, each tube having a cross-sectional diameter between 10 pm and 30 pm, and wherein the particle shows at least 50% of a normalized maximum for each wavelength between 400 nm and 700 nm, wherein the reflectance is normalized to a white diffuser.BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Non-limiting embodiments of the present invention will be described by way of example with reference to the accompanying figures, which are schematic and are not intended to be drawn to scale. In the figures, each identical or nearly identical component illustrated is typically represented by a single numeral. For purposes of clarity, not every component is labeled in every figure, nor is everycomponent of each embodiment of the invention shown where illustration is not necessary to allow those of ordinary skill in the art to understand the invention.

[0012] Figure 1. (A) Macroscopic photograph of a Lunaria annua seedpod showing the matte two external valves surrounding the internal silvery-white septum, along with replum and funicle components. (B) Macroscopic picture of a bent Lunaria septum demonstrating high flexibility. (C) Cross-sectional SEM image of the septum hollow cell bilayer arrays made of cylindrical cells oriented in parallel fashion. (D) High-magnification cross-sectional SEM image of an individual hollow cell with visible thin-film assembly in the cell wall cladding and alignment of the nanofibrils along the cell circumference. (E) Representative weight-normalized cumulative volume of intruded mercury as a function of the applied pressure.

[0013] Figure 2. Fourier-transform infrared spectroscopy (FTIR) confirms the presence of aromatic groups in the L. annua septum (inner) and in the L. annua valves (outer). These spectral fingerprints can be attributed to lignin.

[0014] Figure 3. (A) Top view SEM image of a L. annua septum showing multidomain structure made by ID arrays of cylindrical cells oriented in parallel fashion inside each domain. Scalebar is 100pm. (B) A schematic representation of the multidomain structure of the septum.

[0015] Figure 4. (A) A cross-sectional SEM image of the septum shows the bilayer arrangement of the hollow cell arrays. Scalebar is 10pm. (B) A schematic representation with measurements taken from the SEM image.

[0016] Figure 5. (A) A high-magnification cross-sectional SEM image of an individual hollow cell. Scalebar is 2pm. (B) The thin-film assembly in the cell wall cladding and alignment of the nanofibrils along the cell circumference. (C) A schematic representation of a cross-section of a cell with aligned nanofibrils in the cell wall and a layered cell wall.

[0017] Figure 6. (A) Bright-field reflection micrograph of the septum surface observed in top view showing thin-film interference-like colors spanning the entire visible spectrum. (B) Reflectance spectra collected within single-colored regions, reflecting magenta (1), blue (2), and green (3), and corresponding optical micrographs (white circle indicates the fiber collection spot, 0 ~4 pm, normalized to a white diffuser). (C) Reflectance spectra of the septa collected over large areas, normalized to a white diffuser. Normalization with respect to a silver mirror is a standard reference and is typically used when evaluating strongly reflecting materials. Normalization with respect to a white diffuser is generally used when estimating the overall “whiteness” of a material. This type of reference is used for materials that are more scattering.

[0018] Figure 7. (A) Bright-field reflection micrograph of the septum surface observed in top view showing thin-film interference-like colors spanning the entire visible spectrum. (B) Averagereflectance spectrum of the L. rediviva septa collected over large areas (collection spot 0-60 pm, normalized to a silver mirror) as indicated by the solid black line and standard deviation by the shaded areas. N=30, reported values are average ± standard deviation.

[0019] Figure 8. (A) Average reflectance spectrum of the Lunaria annua septa collected over large areas (collection spot 0-60 pm, normalized to a white diffuser) as indicated by the solid black line and standard deviation by the shaded areas. (B) Average reflectance spectrum of the Lunaria annua septa collected over large areas (collection spot 0-60 pm, normalized to a silver mirror) as indicated by the solid black line and standard deviation by the shaded areas. (C) Comparison of the average reflectance of the Lunaria annua (light gray band) and of the Lunaria rediviva (dark gray band) collected over large areas (collection spot 0~6O pm, normalized to a silver mirror). For each graph: N=30, reported values are average ± standard deviation.

[0020] Figure 9. Photograph of Lunaria septa after grinding and sieving with a 700 pm sieve.

[0021] Figure 10. After grinding, the Lunaria septa flakes are heterogeneous in size and shape. The bilayer structure of the Lunaria septum is retained as well as the hierarchical assembly of the fibrils as confirmed by optical and electron microscopy.

[0022] Figure 11. Bright-field reflection micrographs of a flake (A) and of a fiber (B) microparticle showing thin-film interference colors.

[0023] Figure 12. Top view SEM images of a large (A) and of a small (B) microparticle showing a similar morphology to the septa before any grinding.

[0024] Figure 13. (A-D) Bright-field reflection micrographs of the microparticles after size sorting through sieves with various mesh sizes.

[0025] Figure 14. (A) FTIR absorbance spectra for the Lunaria septum (1) and valve (2) showing aromatic vibrations at - 1596 cm1and 1506 cm1. (B) Absorbance of the Lunaria septum (1) and of the Lunaria microparticles (2) compared to the absorbance of a commercially available dark lignin (3) and of the substrate, an empty well (4).

[0026] Figure 15. (A) Average reflectance spectrum of the Lunaria whole (integer) septa, of the fine microparticles (53 pm fraction), and of the coarse microparticles (53-106 pm fraction) collected over large areas (collection spot 0~6O pm, normalized to a silver mirror) as indicated by the solid black lines and standard deviation by the shaded areas. N=30, reported values are average + standard deviation. (B, C, and D) Bright-field reflection micrographs of the integer septa (B) and of the fine (C) and coarse (D) microparticles.

[0027] Figure 16. Thermal plots of the temperature as a function of time for (A) an individual aluminum block; (B) an aluminum block coated with one lunaria septum; (C) an aluminum block coated with two lunaria septa; (D) an aluminum block coated with lunaria powder. (E) Schematicrepresentation of the used setup. The aluminum cube (black square in the schematic) is placed on a stand, heated with a thermal lamp from above and its temperature as a function of time is recorded using a thermal camera (FLIR). A cold plate is used to simulate environmental conditions.DETAILED DESCRIPTION OF THE INVENTION

[0028] Before the present invention is described in further detail, it is to be understood that the invention is not limited to the particular embodiments described. It is also understood that the terminology used herein is for the purpose of describing particular embodiments only, and is not intended to be limiting. The scope of the present invention will be limited only by the claims. As used herein, the singular forms "a", "an", and "the" include plural embodiments unless the context clearly dictates otherwise.

[0029] Specific structures, devices, and methods relating to surface patterning are disclosed. It should be apparent to those skilled in the art that many additional modifications beside those already described are possible without departing from the inventive concepts. In interpreting this disclosure, all terms should be interpreted in the broadest possible manner consistent with the context. Variations of the term "comprising" should be interpreted as referring to elements, components, or steps in a nonexclusive manner, so the referenced elements, components, or steps may be combined with other elements, components, or steps that are not expressly referenced. Embodiments referenced as "comprising" certain elements are also contemplated as "consisting essentially of" and "consisting of" those elements. When two or more ranges for a particular value are recited, this disclosure contemplates all combinations of the upper and lower bounds of those ranges that are not explicitly recited. For example, recitation of a value of between 1 and 10 or between 2 and 9 also contemplates a value of between 1 and 9 or between 2 and 10.

[0030] Lunaria silvery septa may be used as a passive thermal insulating coating material. The silvery septum may be found in the fruit of the Lunaria annua plant. The Lunaria genus is comprised of three species: Lunaria annua, Lunaria redidiva, and Lunaria telekiana, all with comparable optical properties. The Lunaria silvery septa in its naturally occurring form and / or compositions thereof may be able to decrease the temperature of the material it is applied onto. For example, temperature decreases may range from ~5 °C to ~7°C, or the like. Without wishing to be bound by any particular theory, it is believed that the cellulose hierarchical arrangement combined with the high porosity of the septa (~ 72%) may account for the thermal insulating properties.

[0031] Lunaria is a fully natural material that does not pose biodegradation threats. Lunaria septa can be harvested from the plants that produce them without the need for any genetic modification of the plant or special care. The lunaria silvery septa are made of cellulose and lignin fibers that are natural fibers. The septa may be used as they are without any further chemical modification after harvestingor can be mechanically processed (e.g., milling to form microparticles) to transform the material into a powder made of microparticles. Microparticles can be mixed with a liquid carrier (e.g., water) and cast or spray coated, or otherwise applied or disposed, on surfaces / articles / materials to create conformal coatings. Using the naturally produced lunaria septa or a processed form thereof as a material with passive thermal insulating properties addresses at least the following problems: lack of large-scale thermoregulating coatings; lack of flexible and conformal thermoregulating coatings; lack of biodegradable thermoregulating coatings, and the like.Compositions

[0032] The present disclosure provides novel compositions including particles that can be formulated into compositions that can be used in passive thermal insulating applications. According to an aspect disclosed herein, the compositions can include microparticles derived from Lunaria seedpod septa. The structure and reflective properties of Lunaria seedpod septa are described in “Silique valves as sails in anemochory of Lunaria (Brassicaceae)” C. Leins, P. Fligge, K. Erbar, Plant Biol. 2018, 20, 238 and “Multiscale assembly of reflective cellulose sheets in Lunaria annua,” by G. Guidetti, H. Sun, B. Marelli, F. G. Omenetto, Sci. Adv. 2020, 6, eaba8966, incorporated herein by reference in their entirety. Briefly, the seedpods from Lunaria (including for example L. rediviva and L. annua) contain cellulose and aromatic compounds such as lignin. The macroscopic and microscopic structural details of Lunaria seedpods are shown in Figures 1-8. The Lunaria seedpods consist of a capsule of three flat elliptical membranes: the two external matte valves create a silicle for the development of the seeds, which originate from the internal septum (Figure 1A, Lunaria annua seedpod). Lunaria septa have a distinctive silvery-white reflective appearance at the macroscale that originates from microscale structure and are flexible (Fig. IB). This coloration originates from the thin- film assembly of cellulose fibers in the cells of the septum (Figure 1C and ID) that induce thin-film interference-like colors at the microscale and a silvery-white reflectance at the macroscale due to the additive color mixing principle. The hollow core cylindrical cells are arranged in a parallel fashion within each domain of the bilayer structure of the septum (Error! Reference source not found.C) and are each formed by the cellulose fibrils (Figure ID). The hollow-core structure of the cells accounts for the lightweight of the septa and for the high porosity (>70%) as measured by mercury porosimetry (Figure IE). The seedpods are fully natural materials containing cellulose and aromatic compounds such as lignin. These fruits are collected from the Lunaria plant in late summer when their appearance is silvery- white, stored at room temperature in a dry environment, and may be used as they are without any further purification, or may be further processed before use.

[0033] Figure 2 shows the IR absorption properties of the septum (inner) and valve (outer) components of the Lunaria seedpod confirming the presence of lignin. Figure 3 shows the multidomainarrangement of cellulose fibers in the cells of the septum, where domains are groups of parallel fibers. These cellulose fibers induce thin-film interference-like colors at the microscale. A cross-sectional view of a septum in Figure 4 shows the fibers are hollow, grouped in domains where the adjacent fibers are oriented in parallel and are further arranged in bilayer arrays. Figure 5 shows the cell wall includes a multilayered thin-film assembly of parallel fibers.

[0034] As used herein, visually glittery is understood to describe the shimmery or glowing appearance of the inventive Lunaria particles and / or compositions disclosed herein.

[0035] As shown in FIG. 6, individual cells can be individually observed to reflect different colors of light. This reflectance intensity modulation (Fig. 6B) is due to variations in the multilayered thin-film assembly, for example, differences in spacing between the multiple layers of fibers in the cell wall. Macroscopically, the reflected colors merge to create a broadband response and the silvery- white color of the septa.

[0036] As can be seen in Figure 7 and Figure 8, the microscopic properties and reflectance of L. rediviva are comparable to those of L. annua. The L. rediviva septa also have morphology with a parallel orientation of cell fibrils demonstrating thin-film interference colors.

[0037] In embodiments, Lunaria septa exhibit high porosity. Dried Lunaria septa possess a porosity that is at least 40%, at least 50%, at least 60%, at least 70%, at least 80%, or at least 90%. Lunaria septa may possess a cumulative volume of intruded mercury as measured by mercury porosimetry of at least 0.2 mL / g, 0.5 mL / g, at least 1 mL / g, at least 1.5 mL / g, at most 1.8 mL / g, at most 1.5 mL / g, at most 1 mL / g, at most 0.5 mL / g, or at most 0.2 mL / g.

[0038] The high porosity of the Lunaria valves lends itself to be a potentially thermally insulating material.For example, the temperature decrease by using one or more layers of Lunaria septa or a composition of Lunaria on an object may be at least 4 °C, at least 5 °C, at least 6 °C, at least 7 °C, at least 8 °C, at least 9 °C, at least 10 °C.Methods of forming passive thermal insulating composition

[0039] A composition that provides passive thermal insulation can be fabricated from dried Lunaria septa according to the following general steps: cooling, fragmenting, fractionating. The dried Lunaria septa can further be combined with a carrier.

[0040] Initially, the Lunaria can be harvested at a time when the seedpods are silvery-white and possess a broadband surface reflectance that is at least 40% of a normalized maximum for each wavelength between 400 nm and 700 nm. Alternatively, the Lunaria can be harvested when the silvery- white seedpods have a broadband reflectance that is at least 50%, at least 60%, at least 70%, at least 80%, or at least 90% of a normalized maximum for each wavelength between 400 nm and 700 nm.

[0041] In a first step, dried Lunaria septa can be isolated from the seedpod by any suitable means, such as mechanical, automated, or manual means. The dried Lunaria septa can be separated from the valves, seeds, replum, siliques, and any other residual components.

[0042] Once the dried Lunaria septa are isolated, the septa are coarsely ground or otherwise fragmented to form flakes or thin macroscopic particles of a few millimeters in length and width. In one example, the dried Lunaria septa can be fragmented by grinding using an electric grinder operating between 50 rpm and 20,000 rpm.

[0043] Under cryogenic conditions, the macroparticles can be further fragmented to form microparticles. Cooling to low temperatures causes the septa to become brittle and to fragment into flakes that maintain the microscopic structure of the septa.

[0044] The macroparticles can be cooled to a temperature below the freezing point of water for fragmenting. In one example, the macroparticles can be immersed in liquid nitrogen for at least 3 minutes to cool them to -196 °C. Alternatively, the dried Lunaria septa can be cooled to a low temperature, for example, the temperature can be below -10 °C, below -50 °C, below -100 °C, or below -150 °C by submerging the septa in a thermal bath.

[0045] The macroparticles can be finely ground to microparticles using a mill. In an example, the mill is a ball mill. In another example, the mill is a loot mill. In another example, the mill is a highspeed analytical mill with cooling. In one example, the septa can be fragmented using a ball mill operating at a speed between 15 rpm and 40,000 rpm while maintaining the temperature of the microparticles during grinding. In one example, the temperature can be maintained between 25 °C and -200 °C during the grinding. In another example, the temperature can be maintained between -15 °C and -200 °C during the grinding. In another example, the temperature can be maintained between -70 °C and -200 °C during the grinding. Alternatively, fragmenting can be accomplished by any mechanical means that apply shear forces, impact, or cavitation to form microparticles from the dried Lunaria septa. Additionally, and alternatively, the fragmenting can be accomplished using chemical means, for example oxidative reactions or enzymatic activity (e.g., lignase).Structure and optical properties of microparticles

[0046] In one embodiment, the microparticles are carefully processed to maintain the microscopic structure and optical properties of the whole septa as shown in Figures 9-15. The microparticles obtained from the grinding of the Lunaria annua septa include bilayer assemblies of cellulose tubes, organized as hollow-core cylindrical cells. The microparticles produce a glitter effect as can be seen in Figure 9. As can be seen in Figure 10, the microparticles can be characterized as thin fibers or flakes having uneven edges. The flake microparticles can include multiple parallel fibers as found in a domain. (Figures 10-12) A first distance between opposite sides of the microparticles can be betweenabout 20 pm and 200 pm. A second distance between opposite sides of the microparticles can be between 1000 pm and 200 pm. In another case, the first distance can be between about 15 pm and 160 pm and the second distance can be between 50 pm and 380 pm. In one example, the microparticles can have an aspect ratio (such as first distance: second distance) of between 1 : 1 and 1 :100. The thickness of the microparticles can be about 18 pm, based on the bilayer thickness measured in the cross-sectional view (Figure 4A).

[0047] Fractionation can include separation of flakes, or microparticles having multiple adjacent fibers from microparticles having single fibers. The microparticles can be fractionated or sorted by size by any suitable means such as sieving, centrifugation, or sedimentation. In one example, as shown in Figure 13, sieves with various mesh sizes such as 710 pm, 106 pm, and 53 pm can be used to sort the microparticles.

[0048] In Figure 13, the panels labeled 710 pm, 106 pm, and 53 pm show the microparticles that went through the 710 pm, 106 pm, and 53 pm sieve, respectively. The 53-106 pm fraction consists of microparticles that went through the 106 pm sieve but not the 53 pm sieve. The fractions obtained using smaller mesh sizes show fewer microparticles that retained the thin-film interference colors, along with particles that lost that characteristic coloration. In this example, sieving allows size-sorting of the microparticles into fractions with microparticles having average width that ranges from (120 ± 46) pm to (28 ± 13) pm and length that ranges from (266 + 120) pm to (72 + 23) pm for mesh sizes of 710 pm and 53 pm, respectively (See Table 1).Table 1. Size distribution of the microparticles width and length after the sieving process. For each sieve mesh size, the reported values are the average (avg) ± standard deviation (st. dev.) for n measured microparticles.Width Length sieve mesh size avg ± st. dev. avg ± st. dev. n[pm] [pm] [pm]710 120.3 + 45.9 265.8 + 119.7 96106 45.9 + 24.5 102.2 + 46.9 10053-106 77.1 + 22.6 160.8 + 56.8 10053 28.4 + 13.2 72.1 + 22.8 100

[0049] The glitter effect is observed following the grinding process, as can be seen in Figure 9. The thin-film interference colors in individual cells and fibers are observed at higher magnification of the microparticles. (Figure 11 A) Unexpectedly, the careful generation of these smaller particles correlates with a shift in coloration from silvery-white to light gold due to changes in the lignin structure duringprocessing. The optical properties of microparticles can be more specifically compared to the whole Lunaria septa (Figures 14-15). As can be seen in Figure 14A, the FTIR spectral fingerprints at ~ 1596 cm'1and 1506 cm'1can be attributed to lignin compounds. Figure 14 shows that the absorbance of Lunaria septa and Lunaria microparticles are comparable, while lower than the absorbance of a lignin control sample.

[0050] Similarly, the normalized broadband reflectance across the visible range typical of the L. annua septa is similar for microparticles in the 53-106 pm fraction and 53 pm fraction as can be seen in the overlapping regions in Figure 15 A. The normalized broadband reflectance is somewhat lower for microparticles (~4%) as compared to the whole septa (~6%). Figures 15B-D show the structural differences between the whole septum with multidomain structure (Figure 15B) and the flake microparticle fractions of 53-106 pm and 53 pm (Figures C and D) each having smaller domain representations. Thus, the processing of the septa results in fabrication of microscale highly reflective cellulose microparticles that can be used as UV and visible light filters, and in thermoregulating applications.Carrier

[0051] After fractionation, the microparticles can be included in a composition. The composition of the present disclosure can be formulated into a variety of product forms including liquids, gels, oils, coating materials, filling materials, insulating materials, and spray casts / sprays. These product forms can be used for applications, including, but not limited to, insulation, coatings, spray-on products, aerosols, spray casting products, paints, infrastructure, building, environmental uses, clothing, fabrics / textiles, photovoltaics, energy-related applications, and other applications involving thermoregulation. Any additional components required to formulate such products vary with product type and / or application and can be routinely chosen by one skilled in the art.

[0052] The composition can include a carrier. The carrier can be chosen according to the desired application. For example, water may be a carrier for certain applications while an organic solvent may be a useful carrier for other applications.

[0053] The carrier can optionally be an emulsion. For example, suitable emulsions include oil-in- water, water-in-oil, water-in-oil-in-water, oil-in-water-in-oil, and oil-in-water-in-silicone emulsions.

[0054] The composition can be formulated as an aerosol and applied to the material as a spray-on product, in which case a propellant can be added to the composition. Examples of suitable propellants include butane, isobutane, propane, isopentane, and chlorofluorinated lower molecular weight hydrocarbons. For example, the composition may be applied to walls, roofs, windows, doors, parking lots, runways, hoods, vehicle bodies, fuselage, airplane wings, tents, fabrics, textiles, hats, clothing,semiconductors, microchips, high-power electronic equipment, electric vehicle components, hybrid vehicle batteries, and the like to provide passive thermal cooling.

[0055] The carrier can include one or more optional components including emulsifiers, emollients, or thickening agent.

[0056] The carrier can include emulsifiers. Emulsifiers generally serve to reduce the interfacial tension between phases and improve the formulation and stability of an emulsion. Suitable types of emulsifiers include esters of glycerin, esters of propylene glycol, fatty acid esters of polyethylene glycol, fatty acid esters of polypropylene glycol, esters of sorbitol, esters of sorbitan anhydrides, carboxylic acid copolymers, esters and ethers of glucose, ethoxylated ethers, ethoxylated alcohols, alkyl phosphates, polyoxyethylene fatty ether phosphates, fatty acid amides, acyl lactylates, soaps and mixtures thereof.

[0057] The carrier can optionally include one or more thickening agents. Examples of thickening agents include carboxylic acid polymers, crosslinked polyacrylate polymers, polyacrylamide polymers, polysaccharides, and gums.

[0058] In another example, the carrier can optionally include one or more of a naturally derived oil, such as raspberry oil, carrot oil, wheat germ oil, walnut oil, or buriti oil. In an example, carrier can optionally include one or more of propolis, shea butter, alder buckthorn components, or aloe vera.

[0059] The carrier may be a fiber forming a component of an insulating filling material. In an embodiment, the fiber may be coated with the composition, spun or woven from, or woven with, the composition, extruded with the composition, or otherwise formed in association with the composition.

[0060] The compositions of the present disclosure may contain a variety of optional ingredients. Examples of these ingredient classes include: abrasives, absorbents, aesthetic components such as fragrances, pigments, colorings / colorants, essential oils, skin sensates, astringents, etc. (e.g., clove oil, menthol, camphor, eucalyptus oil, eugenol, menthyl lactate, witch hazel distillate), , anti-caking agents, antifoaming agents, antimicrobial agents (e.g., iodopropyl butylcarbamate), antioxidants, binders, biological additives, buffering agents, bulking agents, chelating agents, chemical additives, colorants, denaturants, drug astringents, external analgesics, opacifying agents, pH adjusters, reducing agents, sequestrants, pantothenic acid and its derivatives, allantoin, bisabolol, and dipotassium glycyrrhizinate), or thickeners.

[0061] Formulations / compositions may include mixtures of microparticles at 0.3 wt%, 0.6 wt%, or 1.2 wt%. Fractionated microparticles of any size grouping can be in a mixture or solution in a weight percentage between 0.1 wt% and 5wt%. For example, microparticles can be combined with a carrier in loadings of 0.1 wt%, 0.2 wt%, 0.3 wt%, 0.4 wt%, 0.5 wt%, 0.6 wt%, 0.7 wt%, 0.8 wt%, 1.0 wt%, 1.1 wt%, 1.2 wt%, 1.3 wt%, 1.4 wt%, 1.5 wt%, 1.6 wt%, 1.7 wt%, 1.8 wt%, 1.9 wt%, 2.0 wt%, 2.1wt%, 2.2 wt%, 2.3 wt%,2.4 wt%, 2.5 wt% 2.6 wt%, 2.7 wt%, 2.8 wt%, 2.9 wt%, 3.0 wt%, 3.1 wt%, 3.2 wt%, 3.3 wt%, 3.4 wt%, 3.5 wt% 3.6 wt%, 3.7 wt%, 3.8 wt%, 3.9 wt%, 4.0 wt%, 4.1 wt%, 4.2 wt%, 4.3 wt%, 4.4 wt%, 4.5 wt% 4.6 wt%, 4.7 wt%, 4.8 wt%, 4.9 wt%, or 5 wt%. For example, microparticles can be combined with a carrier in loadings of between 0.2 wt% and 0.3 wt%, between 0.4 wt% and 0.5 wt%, between 0.8 wt% and 1.2 wt%, between 1.5 wt% and 1.8 wt%, or between 3 wt% and 5 wt%. In yet another example, microparticles can be combined with a carrier in loadings of 0.24 wt%, 0.45 wt%, 1 wt%, 1.67 wt%, or 5 wt%.

[0062] Microparticles of dried Lunaria septa with a carrier such as water for example, may result in increased absorbance over the carrier alone. The wt% loading of microparticles in the carrier can affect the final formulation’s thermoregulating properties. Increased loading or higher wt% of microparticles may result in increased capacity for thermoregulating.

[0063] The size of the microparticles may have some effect on thermoregulating.

[0064] Applications

[0065] The application of the dried Lunaria septa microparticles are multiple. According to an aspect of the disclosure herein, the Lunaria septa and / or microparticles may form a coating material, such as an insulating coating material, for infrastructure and building (e. g., a Lunaria coating could be applied on tiles and roofs to decrease the internal temperature of a building). According to an aspect of the disclosure herein, the Lunaria septa and / or microparticles may form a coating material for the environment (e. g., Lunaria microparticles could be sprayed on glaciers to decrease ice melting caused by increase air temperature). According to an aspect of the disclosure herein, the Lunaria septa and / or microparticles may form an insulating filling material for clothing (e.g., winter jackets). For example, fibers forming a component of an insulating filling material may be coated with the composition or spun from the composition. Further applications may be found in the fields of paints, cloths, photovoltaics, infrastructure, energy-related companies, and the like.

[0066] Thermoregulating compositions can comprise a plurality of forms and the form may be selected for the application in which it is to be used, such as a solution, a mixture, an emulsion, a powder, a dried film, and the like. In another embodiment, the thermoregulating composition can include incorporating the microparticles into a carrier such that the thermoregulating composition can be used to manufacture packaging with thermoregulating behavior. In a further embodiment, the thermoregulating composition can include a carrier that allows the thermoregulating composition to be used as a spray or aerosol. In a still further embodiment, the thermoregulating composition can include a carrier that makes the thermoregulating composition suitable as a paint. The composition could also be used in textile manufacturing to produce thermoregulating fabrics.

[0067] In embodiments, the composition may be disposed on a material at a density of at least 1 .5 mg / cm2, at least 1.75 mg / cm2, at least 2.0 mg / cm2, or at least 2.25 mg / cm2to provide thermoregulation.

[0068] In embodiments, the composition may be disposed on a material at a thickness of at least 0.1 mm, at least 0.2 mm, at least 0.5 mm, or at least 1 mm to provide thermoregulation.

[0069] Miscellaneous

[0070] Unless otherwise specified or indicated by context, the terms “a”, “an”, and “the” mean “one or more.” For example, “a molecule” should be interpreted to mean “one or more molecules.”

[0071] As used herein, “about”, “approximately,” “substantially,” and “significantly” will be understood by persons of ordinary skill in the art and will vary to some extent on the context in which they are used. If there are uses of the term which are not clear to persons of ordinary skill in the art given the context in which it is used, “about” and “approximately” will mean plus or minus <10% of the particular term and “substantially” and “significantly” will mean plus or minus >10% of the particular term.

[0072] As used herein, the terms “include” and “including” have the same meaning as the terms “comprise” and “comprising.” The terms “comprise” and “comprising” should be interpreted as being “open” transitional terms that permit the inclusion of additional components further to those components recited in the claims. The terms “consist” and “consisting of” should be interpreted as being “closed” transitional terms that do not permit the inclusion additional components other than the components recited in the claims. The term “consisting essentially of” should be interpreted to be partially closed and allowing the inclusion only of additional components that do not fundamentally alter the nature of the claimed subject matter.

[0073] All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g., “such as”) provided herein, is intended merely to better illuminate the invention and does not pose a limitation on the scope of the invention unless otherwise claimed. No language in the specification should be construed as indicating any non-claimed element as essential to the practice of the invention.

[0074] All references, including publications, patent applications, and patents, cited herein are hereby incorporated by reference to the same extent as if each reference were individually and specifically indicated to be incorporated by reference and were set forth in its entirety herein.

[0075] Preferred aspects of this invention are described herein, including the best mode known to the inventors for carrying out the invention. Variations of those preferred aspects may become apparent to those of ordinary skill in the art upon reading the foregoing description. The inventors expect a person having ordinary skill in the art to employ such variations as appropriate, and the inventors intend forthe invention to be practiced otherwise than as specifically described herein. Accordingly, this invention includes all modifications and equivalents of the subject matter recited in the claims appended hereto as permitted by applicable law. Moreover, any combination of the above-described elements in all possible variations thereof is encompassed by the invention unless otherwise indicated herein or otherwise clearly contradicted by context.EXAMPLES

[0076] Example 1

[0077] Thermal tests were carried out to investigate if the use of Lunaria as coating on materials could decrease the temperature of those materials (Figure 16). The used setup consisted of evaluating the steady-state temperature reached by an aluminum cube upon air temperature increase using a thermal lamp for the following configurations: aluminum cube alone (Figure 16A); aluminum cube coated with one lunaria septum (Figure 16B); aluminum cube coated with two lunaria septa (Figure 16C); aluminum cube coated with lunaria powder (Figure 16D). For configurations of Figure 16B and 16C, the Lunaria septa were positioned on the block so that the cylindrical cells’ length was parallel to the aluminum top surface and the septa was covering the entire surface of the upper cube face, while for the configuration of Figure 16D microparticles with average size of 700 pm were deposited on the cube with the aid of an adhesive tape at a density of 2.2mg / cm2.

[0078] Materials coated with one or more Lunaria septa or Lunaria powder were evaluated to determine the temperature reached at equilibrium. The presence of the Lunaria decreases the temperature reached by the metallic cube coated with Lunaria septa or powder. Table 2 reports average temperature (Tayg) and temperature difference (AT) reached for the investigated configurations. For each configuration, the reported values are the average (avg) ± standard deviation (st. dev.). Temperature difference was calculated as the difference between the aluminum cube with the addition of the Lunaria coating and with the aluminum cube alone. Specifically, a higher decrease in temperature can be reached by using 2 layers of Lunaria instead of a single one (ATI lunaria = 5.22°C, AT2 lunaria = 7.19°C) . The measured temperature difference values , AT, are comparable with or higher than some engineered lab-fabricated polymer-based structures (AT ~ 2-5 °C).TABLE 2 TavgAT configuration avg ± st. dev. [°C] avg [°C]Aluminum 44.66 ± 1.67Aluminum + 1 Lunaria septum 39.43 ± 0.72 5.22Aluminum + 2 Lunaria septa 37.47 ± 0.97 7.19Aluminum + Lunaria powder 39.24+ 0.03 5.42

[0079] Preferred aspects of this invention are described herein, including the best mode known to the inventors for carrying out the invention. Variations of those preferred aspects may become apparent to those of ordinary skill in the art upon reading the foregoing description. The inventors expect a person having ordinary skill in the art to employ such variations as appropriate, and the inventors intend for the invention to be practiced otherwise than as specifically described herein. Accordingly, this invention includes all modifications and equivalents of the subject matter recited in the claims appended hereto as permitted by applicable law. Moreover, any combination of the above-described elements in all possible variations thereof is encompassed by the invention unless otherwise indicated herein or otherwise clearly contradicted by context.

[0080] Unless otherwise specified or indicated by context, the terms “a”, “an”, and “the” mean “one or more.” For example, “a molecule” should be interpreted to mean “one or more molecules.”

[0081] As used herein, “about”, “approximately,” “substantially,” and “significantly” will be understood by persons of ordinary skill in the art and will vary to some extent on the context in which they are used. If there are uses of the term which are not clear to persons of ordinary skill in the art given the context in which it is used, “about” and “approximately” will mean plus or minus <10% of the particular term and “substantially” and “significantly” will mean plus or minus >10% of the particular term.

[0082] As used herein, the terms “include” and “including” have the same meaning as the terms “comprise” and “comprising.” The terms “comprise” and “comprising” should be interpreted as being “open” transitional terms that permit the inclusion of additional components further to those components recited in the claims. The terms “consist” and “consisting of” should be interpreted as being “closed” transitional terms that do not permit the inclusion of additional components other than the components recited in the claims. The term “consisting essentially of’ should be interpreted to be partially closed and allowing the inclusion only of additional components that do not fundamentally alter the nature of the claimed subject matter.

[0083] All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g., “such as”) provided herein, is intended merely to better illuminate the invention and does not pose a limitation on the scope of the invention unless otherwise claimed. No language in the specification should be construed as indicating any non-claimed element as essential to the practice of the invention.

[0084] All references, including publications, patent applications, and patents, cited herein are hereby incorporated by reference to the same extent as if each reference were individually and specifically indicated to be incorporated by reference and were set forth in its entirety herein.

[0085] Preferred aspects of this invention are described herein, including the best mode known to the inventors for carrying out the invention. Variations of those preferred aspects may become apparent to those of ordinary skill in the art upon reading the foregoing description. The inventors expect a person having ordinary skill in the art to employ such variations as appropriate, and the inventors intend for the invention to be practiced otherwise than as specifically described herein. Accordingly, this invention includes all modifications and equivalents of the subject matter recited in the claims appended hereto as permitted by applicable law. Moreover, any combination of the above-described elements in all possible variations thereof is encompassed by the invention unless otherwise indicated herein or otherwise clearly contradicted by context.

[0086] While the invention has been illustrated and described in detail in the foregoing drawings and description, the same is to be considered as illustrative and not restrictive in character, it being understood that only illustrative embodiments thereof have been shown and described and that all changes and modifications that come within the spirit of the invention are desired to be protected. For example, any of the features or functions of any of the embodiments disclosed herein may be incorporated into any of the other embodiments disclosed herein.

[0087] The following examples illustrate some embodiments and aspects of the invention. It will be apparent to those skilled in the relevant art that various modifications, additions, substitutions, and the like can be performed without altering the spirit or scope of the invention, and such modifications and variations are encompassed within the scope of the invention as defined in the claims which follow. The following examples do not in any way limit the invention.

[0088] EQUIVALENTS AND SCOPE

[0089] The recitation of a listing of elements in any definition of a variable herein includes definitions of that variable as any single element or combinations (or subcombinations) of listed elements. The recitation of an embodiment herein includes that embodiment as any single embodiment or in combination with any other embodiments or portions thereof. Those skilled in the art will recognize, or be able to ascertain using no more than routine experimentation, many equivalents to the specific embodiments of the invention described herein. The scope of the present invention is not intended to be limited to the above Description, but rather is as set forth in the following claims:

Claims

CLAIMS1. A method of preparing a thermoregulating composition, the method comprising: submerging dried Lunaria septa in a thermal bath at a temperature of below -10 °C, below - 50 °C, below -100 °C, below -150 °C, below -195 °C or in liquid nitrogen for at least 10 seconds, at least 30 seconds, at least 1 minute, at least 2 minutes, at least 2 minutes 30 seconds, or at least 3 minutes; fragmenting the dried Lunaria septa to microparticles while maintaining a temperature of the dried Lunaria septa below 15 °C; and fractionating the microparticles, wherein the submerging, fragmenting, and / or fractionating are adapted to provide desired thermoregulating properties.

2. The method of claim 1 , the method further comprising combining the microparticles with a carrier in a weight ratio between 0.1 and 25 wt%.

3. The method of any one of the preceding claims, wherein the dried Lunaria septa possess a porosity that is at least 40%, at least 50%, at least 60%, at least 70%, at least 80%, or at least 90%.

4. The method of any one of the preceding claims, wherein the seedpods have a white or yellow appearance.

5. The method of any one of the preceding claims, wherein the fragmenting is mechanical fragmenting.

6. The method of the immediately preceding claim, wherein the mechanical fragmenting includes shear forces, impact, or cavitation.

7. The method of any one of claims 1 to 3, wherein the fragmenting is chemical fragmenting.

8. The method of any one of the preceding claims, wherein the fragmenting is grinding at a temperature of between 25 °C and -200 °C.

9. The method of any one of the preceding claims, wherein the dried Lunaria septa are fragmented by a ball mill operating at a speed between 15 and 40,000 rpm while maintaining a temperature between -15 and -200 °C.

10. The method of any one of the preceding claims, wherein the microparticles are selected to have a range of sizes including a first microparticle size defined by a first distance between opposite sides of the microparticle of between 10 pm and 200 pm and a second microparticle size defined by a second distance between opposite sides of the microparticle of between 1000 pm and 200 pm.

11. The method of any one of the preceding claims, wherein the microparticles have an aspect ratio of between 1 : 1 and 1: 100.

12. The method of any one of the preceding claims wherein the microparticles are fractionated using at least one sieve.

13. The method of any one of the preceding claims wherein the microparticles are fractionated using centrifugation.

14. The method of any one of the preceding claims wherein fractionating the microparticles comprises separating microparticles having multiple adjacent fibers from microparticles having single fibers.

15. The method of any one of the preceding claims, further comprising reducing the septa to macroparticles before fragmenting the septa to microparticles while maintaining a temperature of the septa at or below -1 °C.

16. The method of the immediately preceding claim, wherein the septa are reduced to macroparticles by a grinder with a grinding component rotating between 500 rpm and 20,000 rpm.

17. The method of any one of the preceding claims, wherein the microparticles are characterized by reflectance between 400 nm and 700 nm.

18. The method of any one of the preceding claims, wherein the microparticles are characterized by absorbance between 200 nm and 400 nm.

19. The method of any one of the preceding claims, wherein the carrier is a liquid .

20. The method of any one of the preceding claims, wherein the carrier is a packaging material and comprises at least one of the following: a thermoplastic material, a polymer, monomers, or an adhesive.

21. A composition made by the method of any one of the preceding claims.

22. A composition comprising the microparticles of any one of claims 1 to 18.

23. The composition of claim 21 or 22, wherein the composition is a spray or an aerosol.

24. The composition of claim 21 or 22, wherein the composition is a powder.

25. The composition of claim 21 or 22, wherein the composition is a dried film.

26. A thermoregulating composition comprising fragmented and fractionated dried Lunaria septa, wherein the dried Lunaria septa possess a porosity that is at least 40%, at least 50%, at least 60%, at least 70%, at least 80%, or at least 90% .

27. The composition of the immediately preceding claim, further comprising a carrier.

28. The composition of the immediately preceding claim, wherein the microparticles are mixed with the carrier at between 0.2 wt% and 5 wt%.

29. The method or composition of any one of the preceding claims, wherein the Lunaria isLunaria annua.

30. The method or composition of any one of claims 1 to the claim immediately preceding the immediately preceding claim, wherein the Lunaria is Lunaria rediviva or Lunaria telekiana.

31. The method or composition of any one of the preceding claims, wherein the dried Lunaria septa possess a cumulative volume of intruded mercury as measured by mercury porosimetry of at least 0.2 mL / g, 0.5 mL / g, at least 1 mL / g, at least 1.5 mL / g, at most 1.8 mL / g, at most 1.5 mL / g, at most 1 mL / g, at most 0.5 mL / g, or at most 0.2 mL / g.

32. A method of using cellulose microparticles for thermoregulation, the method comprising: producing cellulose microparticles from Lunaria septa, wherein the Lunaria septa possess a porosity that is at least 40%, at least 50%, at least 60%, at least 70%, at least 80%, or at least 90%; combining the cellulose microparticles with at least one carrier at or above 1 wt% particle concentration to generate a formulation; and applying the formulation to a material, the cellulose microparticles providing thermoregulation to the material, wherein the microparticles are between 10 pm and 1000 pm in diameter.

33. The method of claim 32, wherein the Lunaria septa possess a cumulative volume of intruded mercury as measured by mercury porosimetry of at least 0.2 mL / g, 0.5 mL / g, at least 1 mL / g, at least 1.5 mL / g, at most 1.8 mL / g, at most 1.5 mL / g, at most 1 mL / g, at most 0.5 mL / g, or at most 0.2 mL / g.

34. The method of claim 32, wherein the formulation is disposed on the material at a density of at least 1.5 mg / cm2, at least 1.75 mg / cm2, at least 2.0 mg / cm2, or at least 2.25 mg / cm2.

35. A thermoregulating composition comprising: a particle comprising greater than 50% cellulose, wherein the particle comprises an array of parallel- arranged cellulose tubes, each tube having a cross-sectional diameter between 10 pm and 30 m, and wherein the particle shows at least 50% of a normalized maximum for each wavelength between 400 nm and 700 nm, wherein the reflectance is normalized to a white diffuser.

36. The thermoregulating composition of the preceding claim, wherein the particle is derived from a Lunaria septa, the Lunaria septa possessing a porosity that is at least 40%, at least 50%, at least 60%, at least 70%, at least 80%, or at least 90%.

37. The thermoregulating composition of the preceding claim, further comprising a carrier suitable for application, cast, or spray on to a material.

38. The thermoregulating composition of the preceding claim, wherein the particle imbues the composition with thermoregulating effects.

39. The thermoregulating composition of claim 35, wherein the particle is derived from a Lunaria septa, the Lunaria septa possessing a cumulative volume of intruded mercury as measuredby mercury porosimetry of at least 0.2 mL / g, 0.5 mL / g, at least 1 mL / g, at least 1.5 mL / g, at most 1.8 mL / g, at most 1.5 mL / g, at most 1 mL / g, at most 0.5 mL / g, or at most 0.2 mL / g.

40. A thermally-regulated article, comprising: the article; and one or more Lunaria septa disposed on a portion of the article.

41. The thermally-regulated article of claim 40, wherein the one or more Lunaria septa are disposed on the portion with a length of the cylindrical cells of the Lunaria septa arranged parallel to a surface of the thermally -regulated article.

42. A thermally-regulated article, comprising: the article; and a composition of any one of the preceding claims disposed on a portion of the article.

43. The thermally-regulated article of claim 42, wherein the composition is in a form of one or more of a powder, a solution, a mixture, an emulsion, a fiber, or a film.

44. The thermally-regulated article of claim 42, wherein the composition comprises cellulose microparticles that are between 10 pm and 1000 pm in diameter.

45. The thermally-regulated article of claim 42, wherein the composition is disposed at a density of at least 1.5 mg / cm2, at least 1.75 mg / cm2, at least 2.0 mg / cm2, or at least 2.25 mg / cm2.

46. The thermally-regulated article of claim 42, wherein the composition is disposed on the portion with the aid of an adhesive.

47. The thermally-regulated article of claim 42, wherein the composition is disposed at a thickness of at least 0. 1 mm, at least 0.2 mm, at least 0.5 mm, or at least 1 mm.

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