Star ring flexible electrode array based on fiber reinforced ionic liquid gel and preparation method thereof

Abstract

The invention discloses a fiber-reinforced ionic liquid gel-based star-ring flexible electrode array and a preparation process thereof, and the flexible sensing array comprises a substrate supporting layer which is made of an elastic breathable material and has a curved surface contour fitting the surface of human skin; the functional composite layer is formed by ternary compounding of an ionic conductive component, a polymer matrix and a network reinforced phase, and the functional composite layer is prepared by combining solution casting with a gradient curing process; and the sensing array layer comprises a plurality of micro-structure sensing units which are arranged in a matrix, and the sensing units adopt bionic layout design to reduce mutual interference. The flexible sensing array has high conductivity (the conductivity is 0.1-1.0 S / m), excellent flexibility (the tensile elongation at break is larger than or equal to 200%) and anti-crosstalk characteristic (the signal crosstalk suppression ratio is larger than or equal to 85%), the problems that the conductivity and the flexibility of a traditional flexible electrode are difficult to consider and multichannel signal crosstalk is caused are fundamentally solved, and high-fidelity signal acquisition and long-term dynamic stability are achieved.

Description

Technical Field

[0001] This invention belongs to the field of flexible electronic materials technology, specifically relating to a multi-dimensional enhanced composite electrode flexible sensing array and its fabrication process. Background Technology

[0002] Against the backdrop of rapid development in wearable electronic devices and smart health monitoring, flexible sensors, as core functional components, directly determine the practical value of the entire system. Traditional flexible electrode materials typically employ a simple blend of a single conductive polymer or conductive filler with an elastic matrix. While this design approach can achieve basic conductivity, it reveals numerous limitations in practical applications.

[0003] The core challenges faced by existing technologies include: First, the inherent contradiction between conductivity and flexibility is difficult to reconcile. High conductivity often comes at the cost of material flexibility, while excessive pursuit of flexibility leads to a significant decrease in conductivity. Second, under dynamic usage environments, the electrical performance stability of traditional electrode materials is insufficient, and repeated stretching and bending can easily cause irreversible structural damage and performance degradation. Third, multi-channel sensor arrays suffer from severe signal crosstalk under complex deformation conditions, and electromagnetic interference and mechanical coupling effects between sensing units seriously affect the accuracy and reliability of signal acquisition.

[0004] Currently, material composites and structural design are commonly used to improve performance. For example, conductive polymers are combined with elastomers to improve flexibility, or ionic liquids are introduced into polymer networks to improve conductivity. However, these methods still have limitations: a single material system cannot simultaneously meet the multiple requirements of high conductivity, excellent flexibility, and biocompatibility; traditional electrode array layouts do not consider the impact of skin deformation on signal transmission, and are prone to signal crosstalk under dynamic usage conditions, leading to distorted monitoring data. Existing technologies lack an effective solution for synergistic optimization and decoupling of overall deformation and local signals from both the material composition and structural design perspectives.

[0005] Therefore, developing a composite electrode sensing array that combines high conductivity, excellent flexibility, and anti-crosstalk properties is of great practical significance for promoting the development of wearable electronics technology. Summary of the Invention

[0006] I. Technical Issues

[0007] To address the shortcomings of existing technologies, this invention provides a multi-dimensional enhanced composite electrode flexible sensing array and its fabrication process, aiming to solve technical problems such as the difficulty in balancing conductivity and flexibility, poor dynamic stability, and crosstalk of multi-channel signals in traditional flexible electrodes.

[0008] II. Technical Solution

[0009] To achieve the above objectives, the present invention adopts the following technical solution:

[0010] A multi-dimensional enhanced composite electrode flexible sensing array, characterized in that it comprises:

[0011] The base support layer is made of elastic and breathable material and has a curved contour that conforms to the surface of human skin.

[0012] The functional composite layer is composed of an ion-conducting component, a polymer matrix, and a network-reinforcing phase in a ternary composite. The functional composite layer is prepared by solution casting combined with gradient curing process.

[0013] The sensing array layer contains multiple microstructure sensing units arranged in a matrix, and the sensing units adopt a biomimetic layout design to reduce mutual interference.

[0014] The mass ratio of the ion-conducting component to the polymer matrix is ​​5%-25%, and the mass fraction of the network reinforcement phase in the functional composite layer is 0.5%-2%.

[0015] As a preferred embodiment, the ionic conductive component is a purified imidazole or pyridine ionic liquid with a purity of not less than 99%.

[0016] As a preferred embodiment, the polymer matrix is ​​medical-grade gelatin, which has good biocompatibility and film-forming properties.

[0017] As a preferred embodiment, the network reinforcement phase is a mixture of nanofibers and polymer microfibers, used to construct a multi-scale three-dimensional network structure.

[0018] As a preferred embodiment, the sensing array layer contains 12 sensing units, adopts an octopus-like topology layout, and the spacing between adjacent sensing units is controlled within the range of 5-15mm.

[0019] As a preferred embodiment, the surface of the functional composite layer is covered with a biocompatible adhesive coating with a thickness of 5-10 micrometers, and the non-functional areas are encapsulated with insulating protective materials.

[0020] As a preferred embodiment, a fabrication process for a multi-dimensional enhanced composite electrode flexible sensing array includes the following steps:

[0021] Step 1: After pulverizing and sieving the medical-grade gelatin, add deionized water at a solid-liquid ratio of 1:10-1:20, stir and dissolve at 50-60℃, and cool to 30-40℃ for later use.

[0022] Step 2: Purify the ionic liquid raw material by rotary evaporation and column chromatography to achieve a purity of over 99%;

[0023] Step 3: Slowly add the purified ionic liquid to the gelatin solution according to the predetermined ratio, and continue stirring under constant temperature conditions;

[0024] Step 4: Add the network-enhancing phase to the mixed solution and disperse it uniformly by ultrasonic treatment;

[0025] Step 5: Add crosslinking agent, continue stirring, and let stand at room temperature to allow the system to undergo initial crosslinking.

[0026] Step 6: Inject the composite solution into the mold and remove air bubbles under vacuum conditions;

[0027] Step 7: Use a two-stage temperature gradient for curing and molding, and obtain the primary electrode material after cooling and demolding;

[0028] Step 8: Perform surface treatment on the primary electrode material, spray a biocompatible adhesive coating, and cure it in a constant temperature and humidity environment.

[0029] Step 9: The target shape is formed through precision machining, and the non-functional areas are insulated and encapsulated to obtain the flexible sensing array.

[0030] As a preferred embodiment, the two-stage temperature gradient curing process in step seven involves first treating at 30°C for 4-6 hours, and then treating at 45-50°C for 8-12 hours.

[0031] As a preferred embodiment, after step eight is completed, a pre-stretching acclimatization treatment is also included, with a pre-stretching range of 5%-10%, repeated 3-5 times.

[0032] III. Beneficial Effects

[0033] Compared with the prior art, the present invention has the following beneficial effects:

[0034] The multi-dimensional enhanced composite electrode flexible sensing array provided by this invention constructs a functional composite system with excellent electrical and mechanical properties through the synergistic effect of ion-conducting components, polymer matrix, and network reinforcement phase. The ion-conducting components endow the material with high conductivity, with the conductivity of the functional composite layer reaching 0.1-1.0 S / m; the polymer matrix provides good flexibility and biocompatibility; and the network reinforcement phase significantly improves the mechanical strength and dynamic stability of the material.

[0035] The innovative sensor array layout of this invention effectively reduces signal crosstalk between channels by optimizing the spatial arrangement and topology of the sensor units. Under dynamic operating conditions, the signal crosstalk suppression rate reaches over 85%, and the fluctuation range of contact resistance is controlled within 10%, ensuring high fidelity and high stability of multi-channel signal acquisition.

[0036] Post-processing techniques such as gradient curing and pre-stretching acclimatization further optimized the mechanical properties and dynamic response characteristics of the material. The prepared flexible electrode material exhibits a tensile elongation at break of no less than 200% and a peel strength exceeding 0.5 N / cm, fully meeting the stringent requirements for long-term dynamic use of wearable devices.

[0037] The multi-dimensional synergistic optimization strategy proposed in this invention not only resolves the inherent contradiction between conductivity and flexibility in flexible electrode materials, but also fundamentally improves the signal fidelity problem of multi-channel sensor arrays. The fabrication process exhibits excellent controllability and repeatability, and the material system is environmentally friendly and biocompatible. This flexible sensor array, integrating high conductivity, high flexibility, high stability, and high anti-interference capabilities, provides a reliable technical solution for wearable health monitoring, intelligent posture management, and human-computer interaction. Attached Figure Description

[0038] Figure 1 This is a practical application diagram of the multi-dimensional enhanced composite electrode flexible sensing array of the present invention;

[0039] Figure 2 This is a stress-voltage comparison diagram of the composite electrode of the present invention and other types of electrodes;

[0040] Figure 3 This is a layout diagram of the octopus-shaped 12-channel electrode array of the present invention;

[0041] Figure 4 These are peel stress diagrams of the composite layer for different contact materials in this invention;

[0042] Figure 5 This is a two-dimensional infrared spectrum of the temperature response structure and hydrogen bond regulation mechanism of the composite system of the present invention;

[0043] Figure 6 These are cell viability characterization diagrams for different materials used in this invention;

[0044] Figure 7 This is a diagram showing the effect of the fiber network of the present invention on improving the surface condition of the sample;

[0045] Figure 8 This is a stress-strain diagram of different fiber contents during the stretching process of this invention. Detailed Implementation

[0046] To make the technical solution of the present invention clearer, the present invention will be described in detail below with reference to specific embodiments and accompanying drawings. It should be noted that the embodiments described below are only some embodiments of the present invention, and not all embodiments. Other embodiments obtained by those skilled in the art based on the teachings of the embodiments of the present invention without creative effort are all within the protection scope of the present invention.

[0047] Example 1

[0048] like Figures 1 to 3 As shown, a multi-dimensional enhanced composite electrode flexible sensing array mainly includes:

[0049] The base support layer, made of elastic and breathable material, has a curved contour that conforms to the surface of human skin, providing overall mechanical support and wearing comfort.

[0050] The functional composite layer is composed of an ion-conducting component, a polymer matrix, and a network reinforcement phase. The functional composite layer is prepared by solution casting combined with gradient curing process and is the core functional part of the sensor array.

[0051] The sensing array layer contains 12 microstructure sensing units arranged in a matrix. The sensing units adopt a biomimetic layout design to reduce mutual interference and are used to achieve simultaneous acquisition of multi-channel signals.

[0052] The ionic conductive component is present in a mass ratio of 5%-25% to the polymer matrix, and the network reinforcement phase has a mass fraction of 0.5%-2% in the functional composite layer. The ionic conductive component is a purified imidazole or pyridine ionic liquid with a purity of not less than 99%. The polymer matrix is ​​medical-grade gelatin, exhibiting good biocompatibility and film-forming properties. The network reinforcement phase is a mixture of nanofibers and polymer microfibers, used to construct a multi-scale three-dimensional network structure.

[0053] The sensor array layer adopts an octopus-like topology, with the spacing between adjacent sensor units controlled within the range of 5-15 mm. This optimized layout can effectively suppress signal crosstalk caused by skin deformation. The surface of the functional composite layer is covered with a biocompatible adhesive coating with a thickness of 5-10 micrometers, and the non-functional areas are encapsulated with insulating protective materials to ensure safety and signal stability.

[0054] Example 2

[0055] like Figure 1 As shown, the fabrication process of a multi-dimensional enhanced composite electrode flexible sensing array specifically includes the following steps:

[0056] Step 1: After pulverizing and sieving the medical-grade gelatin, add deionized water at a solid-liquid ratio of 1:10-1:20, stir and dissolve at 50-60℃, and cool to 30-40℃ for later use.

[0057] Step 2: Purify the ionic liquid raw material by rotary evaporation and column chromatography to achieve a purity of over 99%;

[0058] Step 3: Slowly add the purified ionic liquid to the gelatin solution according to the predetermined ratio, and continue stirring under constant temperature conditions;

[0059] Step 4: Add the network-enhancing phase to the mixed solution and disperse it uniformly by ultrasonic treatment;

[0060] Step 5: Add crosslinking agent, continue stirring, and let stand at room temperature to allow the system to undergo initial crosslinking.

[0061] Step 6: Inject the composite solution into the mold and remove air bubbles under vacuum conditions;

[0062] Step 7: Use a two-stage temperature gradient for curing and molding, that is, first treat at 30℃ for 4-6 hours, then treat at 45-50℃ for 8-12 hours, and obtain the primary electrode material after cooling and demolding.

[0063] Step 8: Perform surface treatment on the primary electrode material, spray a biocompatible adhesive coating, and cure it in a constant temperature and humidity environment for 24 hours.

[0064] Step 9: The target shape is formed through precision machining, and the non-functional areas are insulated and encapsulated to obtain the flexible sensing array.

[0065] After step eight is completed, a pre-stretching acclimatization treatment is also included, with a pre-stretching range of 5%-10% and 3-5 cycles, to improve the dynamic stability and fatigue resistance of the material.

[0066] The working principle of this invention is explained as follows:

[0067] Multi-component synergistic mechanism: The ionic conductive component forms a continuous conductive pathway in the polymer matrix, providing the material with high conductivity; the network reinforcement phase significantly improves the mechanical strength and dynamic stability of the material through the construction of a multi-scale fiber network; the synergistic effect among the three components achieves an optimized balance between conductivity and mechanical properties.

[0068] Topology anti-interference mechanism: The sensor array layer adopts an octopus-like topology layout. By optimizing the spatial arrangement and spacing design of the sensor units, electromagnetic coupling and mechanical crosstalk between adjacent channels are effectively reduced, and the independence and accuracy of multi-channel signal acquisition are improved.

[0069] Gradient curing enhancement mechanism: A two-stage temperature gradient curing process is adopted, which enables the composite system to complete the initial shaping at low temperature and achieve deep cross-linking and structural densification at high temperature, thereby obtaining an ideal microstructure with both high toughness and appropriate rigidity.

[0070] Interface stabilization mechanism: The biocompatible adhesive coating enhances the adhesion between the electrode and the skin, reducing relative slippage during movement; the insulating encapsulation of non-functional areas effectively prevents signal leakage and environmental interference, ensuring the electrical stability and safety of the entire system.

[0071] The performance of the present invention will be described in detail below with reference to experimental data:

[0072] like Figure 4 As shown, within the range of ionic liquid content of 5%-25%, the conductivity of the composite electrode reaches a peak of 0.5 S / m when the content reaches 15%. Further increasing the ionic liquid content does not significantly improve the conductivity and may affect the mechanical properties of the material. Therefore, 15% is the optimal ratio.

[0073] like Figure 5 As shown, when the content of the network reinforcement phase varies in the range of 0.5%-2%, the sample with a content of 1% exhibits the best comprehensive performance, with a tensile elongation at break of 280% and a peel strength of 0.8 N / cm, proving that an appropriate amount of network reinforcement phase can effectively improve the mechanical properties and interfacial bonding strength of the material.

[0074] like Figure 6 As shown, under test conditions simulating dynamic skin deformation, the signal crosstalk rate of the sensor array of this invention is only 8%, which is much lower than the 45% of the traditional parallel line array, verifying the significant effect of topology layout design in suppressing signal crosstalk.

[0075] like Figure 7 As shown, within the tensile strain range of 0-200%, the resistance change rate of the composite electrode of the present invention remains within 10%, while the resistance change rate of the ordinary composite electrode without network reinforcement phase is as high as 35%, which fully demonstrates the important role of network reinforcement in improving dynamic stability.

[0076] Based on the above experimental results, this invention successfully constructed a multi-dimensional enhanced composite electrode flexible sensing array. Through synergistic optimization of the ion-conducting component, polymer matrix, and network reinforcement phase, the electrical and mechanical properties of the material were simultaneously improved.

[0077] Experimental data show that the optimized composite electrode achieves a conductivity of 0.5 S / m, a tensile elongation at break ≥200%, and a peel strength ≥0.5 N / cm, fully meeting the requirements for long-term dynamic use of wearable devices. Meanwhile, the octopus-shaped 12-channel electrode array exhibits a signal crosstalk suppression rate ≥85% and a contact resistance change rate ≤10% under dynamic deformation conditions, ensuring high fidelity and high stability for multi-channel signal acquisition.

[0078] The innovative sensor array layout design effectively suppresses multi-channel signal crosstalk. The fabrication process offers good controllability, and the material system is environmentally friendly and biocompatible. This novel flexible sensor array, integrating high conductivity, high flexibility, high stability, and high anti-interference capabilities, provides strong technical support for the development of wearable electronic devices and shows broad application prospects in health monitoring, smart wearables, and human-computer interaction.

[0079] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit it. Those skilled in the art can make various modifications and improvements based on the core ideas of the present invention, and these should all be included within the protection scope of the present invention. The protection scope of the present invention is defined by the appended claims and their equivalents.

[0080] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

[0081] The present invention and its embodiments have been described above. This description is not restrictive, and the accompanying drawings are only one embodiment of the present invention; the actual structure is not limited thereto. In conclusion, if those skilled in the art are inspired by this description and design similar structures and embodiments without departing from the spirit of the invention, such designs should fall within the protection scope of the present invention.

Claims

1. A star-ring flexible electrode array based on fiber-reinforced ionic liquid gel, characterized in that, include: The base support layer is made of elastic and breathable material and has a curved contour that conforms to the surface of human skin. The functional composite layer is composed of an ion-conducting component, a polymer matrix, and a network-reinforcing phase in a ternary composite. The functional composite layer is prepared by solution casting combined with gradient curing process. The sensing array layer contains multiple microstructure sensing units arranged in a matrix, and the sensing units adopt a biomimetic layout design to reduce mutual interference. The mass ratio of the ion-conducting component to the polymer matrix is ​​5%-25%, and the mass fraction of the network reinforcement phase in the functional composite layer is 0.5%-2%.

2. The multi-dimensional enhanced composite electrode flexible sensing array according to claim 1, characterized in that, The ionic conductive component is a purified imidazole or pyridine ionic liquid with a purity of not less than 99%, and the polymer matrix is ​​medical-grade gelatin.

3. The multi-dimensional enhanced composite electrode flexible sensing array according to claim 1, characterized in that, The network reinforcement phase is a mixture of nanofibers and polymer microfibers, used to construct a multi-scale three-dimensional network structure.

4. The multi-dimensional enhanced composite electrode flexible sensing array according to claim 1, characterized in that, The sensing array layer contains 12 sensing units, which adopt an octopus-like topology layout, and the spacing between adjacent sensing units is controlled within the range of 5-15mm.

5. The multi-dimensional enhanced composite electrode flexible sensing array according to claim 1, characterized in that, The surface of the functional composite layer is covered with a biocompatible adhesive coating with a thickness of 5-10 micrometers, and the non-functional areas are encapsulated with insulating protective materials.

6. The fabrication process of a multi-dimensional enhanced composite electrode flexible sensing array according to claim 1, characterized in that, Includes the following steps: Step 1: After pulverizing and sieving the medical-grade gelatin, add deionized water at a solid-liquid ratio of 1:10-1:20, stir and dissolve at 50-60℃, and cool to 30-40℃ for later use. Step 2: Purify the ionic liquid raw material by rotary evaporation and column chromatography to achieve a purity of over 99%; Step 3: Slowly add the purified ionic liquid to the gelatin solution according to the predetermined ratio, and continue stirring under constant temperature conditions; Step 4: Add the network-enhancing phase to the mixed solution and disperse it uniformly by ultrasonic treatment; Step 5: Add crosslinking agent, continue stirring, and let stand at room temperature to allow the system to undergo initial crosslinking. Step 6: Inject the composite solution into the mold and remove air bubbles under vacuum conditions; Step 7: Use a two-stage temperature gradient for curing and molding, and obtain the primary electrode material after cooling and demolding; Step 8: Perform surface treatment on the primary electrode material, spray a biocompatible adhesive coating, and cure it in a constant temperature and humidity environment. Step 9: The target shape is formed through precision machining, and the non-functional areas are insulated and encapsulated to obtain the flexible sensing array.

7. The fabrication process of a multi-dimensional enhanced composite electrode flexible sensing array according to claim 6, characterized in that, The two-stage temperature gradient curing process in step seven involves first treating at 30°C for 4-6 hours, and then treating at 45-50°C for 8-12 hours.

8. The fabrication process of a multi-dimensional enhanced composite electrode flexible sensing array according to claim 6, characterized in that, After step eight is completed, a pre-stretching acclimatization treatment is also included, with a pre-stretching range of 5%-10%, repeated 3-5 times.

9. The multi-dimensional enhanced composite electrode flexible sensing array according to claim 1, characterized in that, The functional composite layer has an electrical conductivity of 0.1-1.0 S / m, a tensile elongation at break of ≥200%, and a peel strength of ≥0.5 N / cm.

10. The multi-dimensional enhanced composite electrode flexible sensing array according to claim 1, characterized in that, The sensor array layer exhibits a signal crosstalk suppression rate of ≥85% and a contact resistance change rate of ≤10% under dynamic deformation conditions.

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