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CN-121975057-A - Bipolar switchable piezoelectric ion mechanoreceptors with built-in synaptic function and preparation method thereof

CN121975057ACN 121975057 ACN121975057 ACN 121975057ACN-121975057-A

Abstract

The invention provides a bipolar switchable piezoelectric ion mechanoreceptor with a built-in synaptic function and a preparation method thereof. This thermal response is based on the phase separation behavior of the polymer network from the ionic liquid. It is another object of the present invention to provide a method for polarity modulation of a piezoelectric signal based on a phase separation mechanism, i.e. a positive to negative piezoelectric signal transition. The invention provides a thermal response ionic gel material which has a uniform cross-linked polymer network structure and takes hydrophobic ionic liquid as a dispersion medium. The polymer network is formed by polymerizing and crosslinking acrylic ester monomers, and the ionic liquid is composed of imidazole cations and fluorine-containing anions.

Inventors

  • CHEN LIE

Assignees

  • 中国农业大学

Dates

Publication Date
20260505
Application Date
20251231

Claims (9)

  1. 1. The ionic gel with the thermal response is characterized by having a uniform cross-linked polymer network structure and taking hydrophobic ionic liquid as a dispersion medium, wherein the polymer network is formed by polymerizing and cross-linking acrylic ester monomers, and the ionic liquid is composed of imidazole cations and fluorine-containing anions.
  2. 2. A method of preparing an ionic gel according to claim 1, comprising the steps of: 1) Fully and uniformly mixing acrylate monomers and ionic liquid according to a certain proportion to obtain a mixed solution A of the high molecular monomers and the ionic liquid, wherein the mass ratio of the high molecular monomers to the ionic liquid in the step 1) is 3:7-8:2; 2) Adding a crosslinking agent with the monomer mole content of 0.2-5% and a photoinitiator with the monomer mole content of 0.05-0.5% into the solution A, and uniformly mixing to obtain a clear and transparent solution; 3) Transferring the obtained clear solution to ultraviolet light for ultraviolet light-initiated free radical polymerization to obtain ionic gel.
  3. 3. The method of claim 2, wherein the structural formula of the acrylic monomer selected in the step 1) is shown as a structure (I), and m is more than or equal to 8 and more than or equal to 3;
  4. 4. The method of claim 2, wherein the structural formulas of anions and cations in the ionic liquid selected in the step 1) are shown as a structure (II), and n is more than or equal to 8 and more than or equal to 1;
  5. 5. The process of claim 2, wherein the organic crosslinking agent in step 2) is one or more of acrylate or acrylamide crosslinking agents, and has a structural characteristic shown in structure (III), wherein p is greater than or equal to 1, q is greater than or equal to 5, and R 1 ,R 2 is independent hydrogen or alkyl with 1-5 carbon atoms;
  6. 6. The process of claim 2, wherein the photoinitiator of step 2) is 2, 2-diethoxyacetophenone having the structural features shown in structure (IV), wherein preferably R 3 ,R 4 is an alkyl group having 1 to 8 carbon atoms;
  7. 7. the method of claim 2, wherein the ultraviolet light in step 3) has a wavelength and power of 365nm ultraviolet light, and the power is in the range of 0.5W/cm 2 ～10W/cm 2 , and the illumination time is in the range of 0.25-1h.
  8. 8. The method of claim 2, wherein in the step 1), the mass ratio of the high molecular monomer to the ionic liquid is 4:6-7:3, and the amounts of the crosslinking agent and the photoinitiator in the step 2) are respectively 0.5% -2% and 0.1% -3% of the molar amount of the organic monomer.
  9. 9. The ionic gel application of claim 1 is characterized in that a gel sheet is assembled at the tip of a mechanical finger, a piezoelectric signal detection circuit is connected, and the piezoelectric signal is synchronously fed back to a mechanical hand control system, when the mechanical hand contacts and grabs a water cup, the piezoelectric signal detected by the piezoelectric gel of the fingertip is positive, the temperature is lower than the early warning gel phase transition temperature, and the grabbing can be completed; In addition, the temperature of the water cup at the moment can be read simultaneously by utilizing the linear relation between the piezoelectric signal and the temperature after phase separation, the manipulator is controlled to grasp again after waiting for a period of time, the piezoelectric signal is still negative at the moment, the temperature read by the linear relation between the piezoelectric amplitude and the temperature is further utilized, and grasping can be finished when the temperature is lower than the early warning temperature.

Description

Bipolar switchable piezoelectric ion mechanoreceptors with built-in synaptic function and preparation method thereof Technical Field The invention belongs to the technical field of mechanoreceptors. Background Human skin is a highly complex multi-modal tactile sensation system capable of simultaneously detecting and processing a variety of physical stimuli such as pressure, temperature, etc. This system relies on specialized skin receptors to achieve perception by converting physical signals into ionic currents and generating action potentials. This process involves the synergy of mechanically sensitive Piezo channels with neural networks, forming the basis of haptic perception. After signal transduction, synaptic connections support the formation of memory trails and achieve advanced cognitive functions, including dynamic tactile perception and learning, by further processing information through excitatory and inhibitory signals with pulse timing dependent plasticity (STDP). This bio-ion signaling paradigm provides a fundamental demonstration of the development of artificial sensory systems. However, conventional electronic tactile sensors use electronics as information carriers, and while significant progress has been made, the inherent signal differences with biological systems limit seamless integration. This limitation has prompted researchers to explore ion-based mechanical transduction mechanisms that more closely approximate natural sensory processes. Among the various ionic mechanisms, the piezoelectric ion effect has become a particularly promising approach. It generates self-powered ion signals by pressure induced transient separation of anions and cations in a polymer matrix. The mechanism not only replicates the ion communication principle of biological systems, but also has the unique advantages of high charge density, low voltage operation, inherent biocompatibility and the like, and opens up the possibility for creating a real bionic sensory interface for prosthesis, robotics and man-machine interaction systems. Based on Dobashi et al's predecessor work on the piezoionic effect operating mechanism, piezoionic mechanoreceptors have become a promising platform for pressure sensing and direct neuromodulation. These systems utilize the inherent ionic current in the hydrogel matrix to transduce mechanical stimuli into electrical signals, mimicking the principle of biosensing. The voltage magnitude and polarity in such systems results from the differential mobility of cations and anions, resulting in a net charge separation under applied pressure. This basic insight facilitates the rational design of piezoelectric ion responses by manipulating key gel electrolyte parameters, polymer network density, ionic species with tailored hydration radius, and interfacial ion-polymer kinetics. For example, strategies such as selective ion migration, dynamic ion trapping-release mechanisms, and structural asymmetry design have been successfully implemented to increase the electrical output (magnitude of the piezoelectric ion signal) to improve sensor sensitivity. At present, the development of advanced piezoelectric ion mechanoreceptors capable of multi-modal sensing (such as temperature and pressure), pressure gating behavior and neuromorphic signal processing significantly improves the dimension and intelligence level of haptic perception. However, the current technology has significant shortcomings in material level integration of multi-modal sensing and signal processing. In particular, the integration of multi-modal sensing and intrinsic signal processing capabilities into passive dynamic pressure ion sensing materials themselves remains a key blank. This suggests that future research will require beyond optimizing the electrical output of piezoionic materials, and more critical, how to explore how to "in-house intelligence" by embedding stimulus responses and neuromorphic functions into the materials themselves to achieve integrated sensing and processing. Under the technical background, the patent proposes a bipolar switchable piezoelectric ion mechanoreceptor with a built-in synaptic function based on the premise of introducing thermally responsive microphase separation into ionic gel. The ionic gel utilizes phase separation to reconfigure its microstructure and adjust the relative flow rates of cations and anions to achieve a bi-directional piezoelectric ion signal. This temperature-dependent piezoelectric signal inversion provides closed loop feedback to the ionic gel that can be used for control logic. Notably, ionic gels exhibit a linear correlation between their piezoelectric signal and temperature due to the unrestricted movement of ions in the rich solvent region of their phase separated network, which is not possible with conventional homogeneous network gels. This linear relationship enables the piezomechanoreceptors to read the temperature of the target in a manner similar to detecting pressu