Zero-energy-consumption self-adaptive thermal management and tactile perception multifunctional integrated electronic skin

Abstract

The invention relates to a zero-energy-consumption self-adaptive thermal management and tactile perception multifunctional integrated electronic skin and a preparation method and application thereof. The electronic skin adopts a self-assembly multifunctional integrated design and comprises a thermochromic gel and a carbon nanotube composite functional layer, the zero-energy-consumption photo-thermal and radiation cooling dual-mode effect is achieved through a dynamic light absorption-reflection switching mechanism, and passive self-energized work is achieved through the migration effect of space ions in the gel under external force stimulation. According to the innovation of the structure, a solar heating mode and a radiation cooling mode can be automatically switched, and bidirectional self-adaptive heat management is achieved; meanwhile, based on the piezoresistive effect, the device has high-sensitivity electroneurographic signal response to external mechanical stimulation, and the tactile perception function of biological skin is simulated. The electronic skin has the characteristics of flexibility, deformation, zero-energy-consumption heat regulation and bionic perception, and is suitable for the fields of wearable equipment, intelligent robots, human-computer interaction interfaces, bionic perception systems and the like.

Description

Technical Field

[0001] This invention belongs to the field of biomimetic electronic skin, specifically relating to a self-assembled vertical flexible structure based on a thermochromic ionogel and nanomaterial composite. This structure features zero-energy adaptive thermal management and self-powered tactile sensing capabilities, and its fabrication method and applications are also discussed. Background Technology

[0002] Biological skin is a multifunctional organ, possessing not only dynamic thermoregulation capabilities but also serving as a crucial medium for living organisms to perceive their surroundings and acquire information. This provides an ideal biological prototype and functional paradigm for the design of biomimetic electronic skin. Electronic skin is an electronic device that can simulate, reproduce, and even surpass the basic functions of human skin (protection, sensation, and thermoregulation, etc.) through a combination of material and structural design. Its higher level of biomimicry is the foundation for realizing intelligent interaction, thus having a profound impact on intelligent robots, the Internet of Things, and human-machine interfaces. Existing electronic skin has already achieved skin-like tactile functions, and flexible pressure sensors based on micro / nanomaterials have achieved excellent characterization and formed stable feedback by mimicking living organisms to varying degrees. However, replicating the thermoregulation function of living organisms in electronic skin is still limited to simple heating or cooling, and cannot achieve adaptive thermal regulation in complex and variable environments.

[0003] Against this backdrop, thermal management films based on the Janus structure have been developed, but they suffer from fundamental limitations: switching between heating and cooling modes requires mechanical rotation of the heating / cooling side, necessitating additional mechanical energy consumption and failing to achieve completely zero-energy characteristics, and they cannot achieve biomimetic tactile sensing like biological skin. These limitations significantly restrict the application effectiveness of such technologies in complex environments and critical scenarios such as wearable medical devices requiring monitoring without external force assistance. Thermochromic ionogel materials, due to their excellent high flexibility, convenient solution-processable properties, efficient color-changing response under temperature stimulation, and ionic conductivity response under external stimuli, are considered a potential solution to these limitations. The color-changing mechanism of this material lies in the fact that temperature stimulation can drive a phase transition, thereby altering the light refraction within the gel. This provides the necessary prerequisite for autonomous color change and the ability to switch between light absorption and reflection. The sensing mechanism lies in the fact that external stimuli can drive the dynamic migration of anions and cations within the material along the polymer chains, spontaneously generating a measurable induced current, which lays the physical foundation for realizing a self-powered sensing system.

[0004] Therefore, developing an integrated electronic skin that combines a simple structure, zero-energy adaptive thermal management, and biomimetic tactile sensing has become an urgent need to break through the current technological bottlenecks. Summary of the Invention

[0005] 1. Device structure design This invention patent designs a self-powered, zero-energy adaptive thermal management biomimetic tactile sensing electronic skin, the core of which lies in the use of a self-assembled vertical structure. This structure, from top to bottom, consists of: a thermochromic ionogel and a carbon nanotube-deposited ionogel layer.

[0006] Thermochromic ionogel (transmittance >90% at room temperature) autonomously switches between transparent and opaque white states in response to temperature stimulation. The transparent state ensures uninterrupted light absorption, while the white state provides light reflection conditions to achieve radiative cooling. At the same time, the gel provides tactile sensation.

[0007] Specifically, when in a normal temperature transparent state, sunlight passes through and is efficiently absorbed by the carbon nanotube-deposited ionogel layer, achieving solar heating; when the thermochromic ionogel layer is in a high temperature white state, it achieves radiative cooling through a high-reflectance solar spectrum; changes in the intensity of solar irradiation trigger a phase transition cycle of the thermochromic ionogel layer, thereby autonomously switching between heating and cooling modes, and responding to external stimuli based on an ion migration mechanism, outputting sensing signals.

[0008] A self-settled carbon nanotube light-absorbing ionogel functional layer achieves high-efficiency absorption across a broad spectrum from visible to near-infrared wavelengths through the array multiple scattering and light-trapping effects of nanomaterials, electronic band transitions, and plasmon resonance. This broad solar spectral absorption effect enables solar heating.

[0009] 2. Materials Design An ionogel (composed of a thermochromic ionogel self-assembled from carbon nanotubes) was synthesized via photopolymerization as the core functional material. The ionogel was copolymerized from butyl acrylate monomer, 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide ionic liquid, trimethylolpropane ethoxylated triacrylate crosslinking agent, and 1-hydroxycyclohexylphenyl ketone photoinitiator.

[0010] The nanomaterial in the carbon nanotube sedimentation ion gel layer is a carboxyl-functionalized multi-walled carbon nanotube; the nanomaterial can also be replaced by one or more of graphene, transition metal chalcogenides, MXene, black phosphorus, nanostructured silicon, and metal plasma nanostructures.

[0011] 3. Zero-energy adaptive mode and self-powered mechanism By leveraging the difference in migration rates of cations and anions within the gel, an ion concentration gradient is generated under external pressure stimulation, forming a self-driven potential difference that can output neural electrical signals without the need for an external power source.

[0012] Under solar irradiation, the electronic skin undergoes a phase transition, autonomously switching between black and white to form a self-driven solar heating / radiative cooling system. It achieves adaptive thermal management without additional mechanical energy consumption, and the addition of carbon nanotubes enhances light absorption and photothermal conversion efficiency.

[0013] 4. Preparation method Synthesis of thermochromic ionogel precursor: Butyl acrylate monomer, trimethylolpropane ethoxylate crosslinking agent, and 1-hydroxycyclohexylphenyl ketone photoinitiator were mixed in a specific ratio and stirred at room temperature until no obvious solid precipitate remained, indicating complete dissolution. Then, 50% by mass of ionic liquid (IL) 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide was added, and the mixture was vigorously stirred until homogeneous to obtain a transparent and clear precursor solution. Finally, the prepared precursor solution was poured into a self-made polytetrafluoroethylene material mold. Synthesis of electronic skin: Carbon nanotubes were uniformly doped into a thermochromic ion gel precursor solution, which was then poured into a polytetrafluoroethylene mold and allowed to settle naturally for 6 hours. After the carbon nanotubes had settled completely, they were cured under ultraviolet light to crosslink and polymerize, thus obtaining the electronic skin.

[0014] 5. Application Electronic skin is used in wearable devices, smart robots, or biomimetic sensing systems to autonomously regulate local temperature in complex outdoor environments and simultaneously monitor external pressure or tactile information.

[0015] This patented, zero-energy adaptive thermal management and tactile sensing multifunctional integrated electronic skin can autonomously switch between solar heating and radiative cooling modes, achieving bidirectional adaptive thermal management. Simultaneously, based on the piezoresistive effect, it exhibits a highly sensitive neural electrical signal response to external mechanical stimuli, mimicking the tactile sensing function of biological skin. This electronic skin combines flexibility, deformability, zero-energy thermal regulation, and biomimetic sensing characteristics, making it suitable for wearable devices, intelligent robots, human-computer interfaces, and biomimetic sensing systems. Attached Figure Description

[0016] Figure 1 This is a physical image of the multifunctional integrated electronic skin of the present invention, which combines adaptive thermal management and tactile sensing, and its mechanical properties.

[0017] Figure 2 This invention provides the absorption and reflectance under different states (black and white) and the real-time thermal control capability under different illumination amplitudes.

[0018] Figure 3 The present invention records the changes of each stimulus under different conditions and the cycle stability performance (DR) in real time when pressure stimulation is applied.

[0019] Figure 4 This is a schematic diagram illustrating the principle of adaptive thermal regulation and piezoresistive sensing response of the electronic skin of this invention. Detailed Implementation

[0020] like Figure 1 The image shown is a physical diagram of the multifunctional integrated electronic skin of the present invention, which combines adaptive thermal management and tactile sensing, and its mechanical properties. It exhibits excellent performance in color display under normal and high temperature conditions, as well as in bending, twisting, and stretching conditions.

[0021] The core components of each layer of electronic skin and the preparation method of electronic skin are as follows: 1. Synthesis of the precursor for a thermochromic ionogel: Butyl acrylate (BA), a crosslinking agent (ETPTA), and a photoinitiator (PI-184) were mixed in a ratio of 1:0.01:0.07 and stirred at room temperature until no obvious solid precipitate remained, indicating complete dissolution. Then, 50% by mass of the ionic liquid (IL) 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide ([EMIm][TFSI]) was added, and the mixture was vigorously stirred until homogeneous, yielding a clear and transparent precursor solution. Finally, the prepared precursor solution was poured into a self-made polytetrafluoroethylene (PTFE) mold, and the ionogel was named polybutyl acrylate (PBA).

[0022] 2. Synthesis of electronic skin: This skin was synthesized using a one-step co-photopolymerization process. Carbon nanotubes were uniformly doped into a thermochromic ionogel precursor solution, which was then poured into a polytetrafluoroethylene (PTFE) mold and allowed to settle naturally for 6 hours. After the carbon nanotubes had completely settled, the mixture was cured for 100 seconds under 10 W, 365 nm ultraviolet light to achieve cross-linking polymerization.

[0023] By considering the light absorption / reflectivity from different states ( Figure 2 a) In-depth research was conducted, revealing the principle of bidirectional solar heating / radiative cooling and highlighting its adaptive thermal management capabilities under different solar irradiance conditions. Figure 2b). This endows the receptor with environmental thermal sensitivity, enabling self-regulation of temperature perception. Under different environmental temperature conditions in spring and summer, the receptor exhibits a faster rate of warming up with increasing solar irradiance. When the temperature reaches the phase transition temperature, the receptor undergoes a phase transition and turns white, thereby significantly increasing its reflectivity to incident sunlight and causing a temperature drop. Despite continuous external irradiation, its temperature can ultimately be maintained between 26°C (spring) and 30°C (summer) for a period of time, a temperature range that coincides with the human body's thermal comfort range. The receptor exhibits excellent thermal response characteristics, with a maximum solar heating temperature rise of 19.7°C and a maximum radiative cooling temperature drop of 11.3°C. Figure 2 b).

[0024] The tactile sensing performance of the electronic skin was evaluated through systematic pressure response testing. At a 1% instantaneous strain, the response and recovery times were 369 ms and 626 ms, respectively, confirming the fast dynamic response characteristics of the electronic skin and demonstrating its excellent dynamic sensing properties, capable of meeting the requirements of real-time pressure detection and rapid signal processing. It also exhibited high cyclic stability and repeatability under different pressures. Figure 3 ).

[0025] Figure 4 The diagram illustrates the adaptive thermal management principle of the electronic skin. At room temperature, it appears black and possesses excellent solar energy absorption performance. Through a heat conduction mechanism, the absorbed heat is transferred from the high-temperature region to the low-temperature region, causing the temperature to gradually rise. When the temperature reaches the phase transition temperature, the electronic skin turns white, reflecting sunlight and thus achieving a cooling effect. This is a temperature-driven, spontaneous process that requires no energy consumption, achieving zero-energy thermal regulation.

[0026] Figure 4 b illustrates the piezoresistive tactile sensing principle of electronic skin. By utilizing the difference in migration rates of cations and anions within the gel, an ion concentration gradient is generated under external pressure, forming a self-driven potential difference that can output neural electrical signals without an external power source. The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A zero-energy adaptive thermal management and haptic-aware multifunctional integrated electronic skin, characterized in that, It adopts a self-assembled layered structure, which from top to bottom includes: a thermochromic ion gel layer and a carbon nanotube sedimented ion gel layer; The thermochromic ionogel layer is highly transparent at room temperature and transitions to an opaque white state at high temperatures. When in the transparent state at room temperature, sunlight passes through and is efficiently absorbed by the carbon nanotube-deposited ionogel layer, achieving solar heating. When the thermochromic ionogel layer is in the high-temperature white state, it achieves radiative cooling through the high-reflectance solar spectrum. Changes in the intensity of solar irradiation trigger the phase transition cycle of the thermochromic ionogel layer, thereby autonomously switching between heating and cooling modes and responding to external stimuli based on the ion migration mechanism, outputting sensing signals. Carbon nanotube precipitated ionogel layers serve as a broadband, high-efficiency light-absorbing layer to achieve the photothermal conversion function of solar energy.

2. The electronic skin according to claim 1, wherein The thermochromic ionogel layer is formed by copolymerization of monomer butyl acrylate, ionic liquid 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide, crosslinking agent trimethylolpropane ethoxylated triacrylate, and photoinitiator 1-hydroxycyclohexylphenyl ketone.

3. The electronic skin according to claim 1, wherein The nanomaterial in the carbon nanotube sedimentation ion gel layer is a carboxyl-functionalized multi-walled carbon nanotube; the nanomaterial can be replaced by one or more of graphene, transition metal chalcogenides, MXene, black phosphorus, nanostructured silicon, and metal plasma nanostructures.

4. The electronic skin according to claim 2, wherein, When the electronic skin is stimulated by pressure, an anion and cation concentration gradient is generated inside the thermochromic ion gel layer. The difference in ion migration rate forms a self-driven potential difference, which can output neuro-bionic electrical signals without the need for an external power source.

5. The electronic skin according to claim 3, wherein The carbon nanotube ionogel layer achieves broadband and efficient absorption in the visible to near-infrared bands through the array multiple scattering light-trapping effect of nanomaterials, electronic band transitions, and plasma resonance effect.

6. A method for fabricating a zero-energy adaptive thermal management and tactile sensing multifunctional integrated electronic skin, characterized in that: Synthesis of thermochromic ionogel precursor: Butyl acrylate monomer, trimethylolpropane ethoxylate crosslinking agent, and 1-hydroxycyclohexylphenyl ketone photoinitiator were mixed in a specific ratio and stirred at room temperature until no obvious solid precipitate remained, indicating complete dissolution. Then, 50% by mass of ionic liquid (IL) 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide was added, and the mixture was vigorously stirred until homogeneous to obtain a transparent and clear precursor solution. Finally, the prepared precursor solution was poured into a self-made polytetrafluoroethylene material mold. Synthesis of electronic skin: Carbon nanotubes were uniformly doped into a thermochromic ion gel precursor solution, which was then poured into a polytetrafluoroethylene mold and allowed to settle naturally for 6 hours. After the carbon nanotubes had settled completely, they were cured under ultraviolet light to crosslink and polymerize, thus obtaining the electronic skin.

7. Use of a zero-energy self-adapting thermal management and haptics-aware multifunctional integrated electronic skin according to any one of claims 1-5, characterized in that, The electronic skin is applied to wearable devices, intelligent robots, or biomimetic sensing systems to autonomously regulate local temperature in complex outdoor environments and simultaneously monitor external pressure or tactile information.

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