Flexible gel driver with impact resistance and stimulation responsiveness and preparation method thereof

Abstract

The invention discloses a flexible gel driver with impact resistance and stimulation responsiveness, comprising: a support layer composed of a bacterial cellulose membrane and providing structural support; the response layer is composed of polyacrylic acid PAA hydrogel containing metal ion coordinate bonds and can respond to external stimulation; the support layer and the response layer are connected with each other through a hydrogen bond, and the response layer can realize rapid self-deformation and shape memory functions through coordination of metal ions and carboxyl. The flexible gel driver with impact resistance and stimuli responsiveness provided by the invention not only has good stimuli responsiveness, but also has excellent impact resistance.

Description

Technical Field

[0001] The present invention relates to the technical field of flexible materials, and in particular to a flexible gel actuator with impact resistance and stimulus responsiveness and a preparation method thereof. Background Art

[0002] With the development of science and technology, flexible materials have shown broad application prospects in biomedicine, flexible electronics, soft robots and other fields due to their unique properties. Flexible gel materials have good viscoelasticity, adsorption, biocompatibility, energy absorption and elastic recovery capabilities. They have important scientific significance and broad application prospects in the biomedical field, environmental governance field, and engineering technology fields such as flexible electronics and flexible machines.

[0003] Ion gel is a typical flexible gel material composed of a cross-linked support network as a matrix and ionic liquid dispersed in it. Its characteristic is that ionic liquid is used as the dispersed phase of the gel. Stimulus responsiveness can be achieved through careful design of the polymer skeleton and ionic liquid (metal coordination, ion interaction, hydrogen bond, host-guest interaction, dynamic covalent bond, etc.).

[0004] However, the design of traditional stimuli-responsive ion gels usually focuses on achieving excellent stimuli responsiveness. Due to their weak structural integrity, they generally have low mechanical strength and high brittleness, and are easily affected by deformation and external stress, which ultimately leads to severe performance degradation. This is because traditional stimuli-responsive hydrogels lack effective damping mechanisms and unique structural designs, and cannot actively attenuate external impacts and prevent stress concentration. In view of the above well-known problems, there is an urgent need to develop hydrogels with high damping elasticity and excellent stimuli responsiveness to achieve actuation performance against structural damage and sustained deformation. Summary of the invention

[0005] 1. Technical Problems Solved The technical problems to be solved by the present invention are the various problems mentioned in the above background technology, and provide a flexible gel actuator with impact resistance and stimulus responsiveness and a preparation method thereof. Technical Solution

[0006] In order to solve the above technical problems, the present invention provides a technical solution: a flexible gel actuator with impact resistance and stimulus responsiveness, comprising: The support layer, composed of bacterial cellulose membrane, provides structural support; The response layer is composed of polyacrylic acid (PAA) hydrogel containing metal ion coordination bonds and can respond to external stimuli; The support layer and the response layer are connected to each other through hydrogen bonds, and the response layer can achieve rapid self-deformation and shape memory function through the coordination effect of metal ions and carboxyl groups.

[0007] As an improvement, the bacterial cellulose membrane has a thickness of 0.1 mm to 1 mm.

[0008] As an improvement, poly(3,4-ethylenedioxythiophene)-polystyrene sulfonic acid is also added to the PAA hydrogel to improve the conductive properties of the hydrogel.

[0009] As an improvement, a method for preparing a flexible gel actuator having impact resistance and stimulus responsiveness comprises the following steps: S1. Prepare acrylic acid AA, ammonium persulfate APS, N,N′-methylenebisacrylamide MBA, poly(3,4-ethylenedioxythiophene)-polystyrene sulfonic acid, metal chloride and bacterial cellulose membrane; S2, dissolving APS, MBA and poly(3,4-ethylenedioxythiophene)-polystyrene sulfonic acid in AA and H2O in a certain proportion, and forming a pre-gel solution by magnetic stirring; S3, pouring the pre-gel solution into the mold where the bacterial cellulose membrane has been placed, copolymerizing at 60°C for 1 hour to form a preliminary composite hydrogel; S4, immersing the initially formed composite hydrogel in a solution containing metal ions to enhance the structure of the hydrogel through metal coordination; S5. Wash the composite hydrogel to remove excess metal ions and obtain the final flexible gel actuator.

[0010] As an improvement, the concentration of the metal ion solution is 0.5 M, and the treatment time is 30 minutes to 60 minutes.

[0011] As an improvement, the cleaning solution used in the cleaning step is deionized water, and the cleaning times are no less than 3 times to ensure that the excess metal ions are completely removed. Beneficial Effects

[0012] The advantages of the present invention compared with the prior art are: The flexible gel actuator provided by the present invention forms an integral structure by combining a bacterial cellulose membrane as a supporting layer and a polyacrylic acid (PAA) hydrogel containing metal ion coordination bonds as a response layer. The BC film of the present invention has a high modulus. When two materials with inconsistent moduli are subjected to vertical stress, the high modulus carrier BC film will bear greater stress and inhibit the diffusion of stress to the low modulus horizontal carrier through the basic principles of local transmission and diffusion with the medium, thereby effectively improving the damage resistance and stress concentration resistance of heterogeneous materials. At the same time, the present invention makes the structure dense through metal ion coordination bonds, thereby improving the structural strength of the PAA layer. In addition, hydrogen bonds enable the PAA layer and the BC layer to have stable and excellent interlayer bonding force to prevent interface degradation. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a schematic diagram of the structure of a flexible gel actuator with impact resistance and stimulus responsiveness of the present invention.

[0014] Figure 2 The present invention is a flow chart of a method for preparing a flexible gel actuator with impact resistance and stimulus responsiveness.

[0015] Figure 3 This is a gel stretching test diagram of a flexible gel actuator with impact resistance and stimulus responsiveness of the present invention.

[0016] Figure 4 This is a single-side notch test diagram of a flexible gel actuator structure with impact resistance and stimulus responsiveness according to the present invention.

[0017] Figure 5 This is a puncture test diagram of a flexible gel actuator with impact resistance and stimulus responsiveness of the present invention.

[0018] Figure 6 This is an impact test diagram of a flexible gel actuator with impact resistance and stimulus responsiveness according to the present invention. DETAILED DESCRIPTION

[0019] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments; based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention. Example

[0020] like Figure 1 As shown, a flexible gel actuator with impact resistance and stimulus responsiveness comprises: A support layer, composed of a bacterial cellulose membrane, providing structural support, wherein the thickness of the bacterial cellulose membrane is 0.1 mm to 1 mm; The response layer is composed of a polyacrylic acid (PAA) hydrogel containing metal ion coordination bonds and can respond to external stimuli. Poly(3,4-ethylenedioxythiophene)-polystyrene sulfonic acid is also added to the PAA hydrogel to improve the conductivity of the hydrogel. The support layer and the response layer are connected to each other through hydrogen bonds, and the response layer can achieve rapid self-deformation and shape memory function through the coordination effect of metal ions and carboxyl groups. Example

[0021] like Figure 2The method for preparing a flexible gel actuator having impact resistance and stimulus responsiveness comprises the following steps: S1. Prepare acrylic acid AA, ammonium persulfate APS, N,N′-methylenebisacrylamide MBA, poly(3,4-ethylenedioxythiophene)-polystyrene sulfonic acid, metal chloride and bacterial cellulose membrane; S2, dissolving APS, MBA and poly(3,4-ethylenedioxythiophene)-polystyrene sulfonic acid in AA and H2O in a certain proportion, and forming a pre-gel solution by magnetic stirring; S3, pouring the pre-gel solution into the mold where the bacterial cellulose membrane has been placed, copolymerizing at 60°C for 1 hour to form a preliminary composite hydrogel; S4, immersing the initially formed composite hydrogel in a solution containing metal ions to enhance the structure of the hydrogel through metal coordination, wherein the concentration of the metal ion solution is 0.5 M and the treatment time is 30 to 60 minutes; S5. Cleaning the composite hydrogel to remove excess metal ions and obtain the final flexible gel actuator. The cleaning solution used in the cleaning step is deionized water, and the cleaning times are no less than 3 times to ensure that the excess metal ions are completely removed.

[0022] Working principle of the present invention: Structural connection: The bacterial cellulose membrane and PAA hydrogel are connected to each other through hydrogen bonds to form an integral structure.

[0023] Impact resistance principle: The BC film of the present invention has a high modulus. When two materials with inconsistent moduli are subjected to vertical stress, the high modulus carrier BC film will bear greater stress and inhibit the diffusion of stress to the low modulus horizontal carrier through the basic principles of local transmission and diffusion with the medium, thereby effectively improving the damage resistance and stress concentration resistance of heterogeneous materials.

[0024] Heterogeneous structure: Double-layer design stimulus-responsive ion gel. The principle is that different layers have different responses. The PAA layer has the ionic response mentioned above, and the BC layer does not react with iron ions and does not deform, showing an asymmetric response to external stimuli, thereby stimulating deformation.

[0025] Shape recovery: Through the coordination of metal ions and carboxyl groups, the response layer can achieve rapid self-deformation and shape recovery. The deformation time is within 120 seconds. During the recovery process, by immersing the hydrogel in H+ solution, the iron ions are replaced by hydrogen ions, and the metal coordination bonds are dissociated, which weakens its ability to temporarily fix the shape, resulting in shape recovery.

[0026] Conductive properties: The added PEDOT:PSS significantly improved the conductivity of the hydrogel, enabling it to respond quickly under electrical stimulation.

[0027] The following are the performance test experiments of the present invention, specifically including tensile test, puncture test and impact test: like Figure 3 As shown in the figure, the tensile test of the hydrogels of PBC, PAA and BC showed that the toughness of the PBC hydrogel was 375.53 KJ / m 3 , the fracture strength is 794.47 KPa, the fracture strain is 68.11%; the toughness of the PAA hydrogel is 106.70333 KJ / m 3 , the fracture strength is 116.15377KPa, the strain is 136.65867%; the toughness of the BC hydrogel is 241.47667KJ / m 3 , the fracture strength is 4273.0327KPa, and the strain is 9.82337%.

[0028] like Figure 4 As shown in the figure, the tensile test of the hydrogels made of PBC, PAA and BC showed that the fracture energy of the PBC hydrogel was 289 J / m 2 The fracture energy of the PAA hydrogel is 44.83 J / m 2 .

[0029] like Figure 5 As shown, in the puncture test of the hydrogels made of PBCI and PAA, it was found that the maximum puncture force of the PBCI was 4.42N, and the maximum puncture force of the PAA was 0.52N.

[0030] like Figure 6 As shown, impact tests were performed on hydrogels of different materials and it was found that the flexible gel actuator of the present invention can still maintain good structural integrity and mechanical properties when subjected to external impact.

[0031] We propose a scalable and universal engineering strategy for structural integrity hydrogel actuators, which have excellent impact resistance and can achieve ion-triggered programmable deformation. Notably, we verified that the in situ polymerization of hydrogels on cellulose scaffolds regulates structural integrity through the synergistic effect of high-crystalline cellulose domains and abundant hydrogen bonds in the matrix, which helps to obtain excellent interfacial stability to prevent stress concentration, which is much better than the PAA-based hydrogels reported in the literature. At the same time, the hydrogel also has excellent bending stability (50,000 bending cycles), toughness (375.53KJ / m3), puncture resistance (4.42N), and especially has excellent mechanical properties in terms of tear resistance (289J / m2). It can be seen that the double-layer heterogeneous structure hydrogel prepared by this scheme has obvious advantages.

[0032] Secondly, the asymmetric deformation behavior of the soft hydrogel actuator can be quantitatively and reversibly adjusted through dynamic coordination bonds (salt concentration and pH value regulation), and the applications of hydrogel grippers and flower shape memory are further intuitively evaluated. In addition, the asymmetric deformation behavior of the soft hydrogel actuator can be quantitatively and reversibly adjusted through dynamic coordination bonds (salt concentration and pH value regulation), and the applications of hydrogel grippers and flower shape memory are further intuitively evaluated. 2+ , A l3+ 、Zn 2+ ) explored the versatility of the structural design of smart actuators. This ingenious and universal structural design has broad prospects and provides a new perspective for the development of soft actuators with excellent impact resistance and durability.

[0033] In summary, the flexible gel actuator prepared by the above method has broad application prospects in the fields of soft robots, smart wearable devices, biomedical devices, etc. It can achieve precise control and efficient response, and provides new ideas and solutions for the development of related technologies.

[0034] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0035] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

[0036] The present invention and its embodiments are described above, and such description is not restrictive. The drawings show only one embodiment of the present invention, and the actual structure is not limited thereto. In short, if ordinary technicians in the field are inspired by it, without departing from the purpose of the invention, they can design a structure and embodiment similar to the technical solution without creativity, which should belong to the protection scope of the present invention.

Claims

1. A flexible gel actuator having impact resistance and stimulus responsiveness, characterized in that: include: The support layer, composed of bacterial cellulose membrane, provides structural support; The response layer is composed of polyacrylic acid (PAA) hydrogel containing metal ion coordination bonds and can respond to external stimuli; The support layer and the response layer are connected to each other through hydrogen bonds, and the response layer can achieve rapid self-deformation and shape memory function through the coordination effect of metal ions and carboxyl groups.

2. The flexible gel actuator with impact resistance and stimulus responsiveness according to claim 1, characterized in that: The thickness of the bacterial cellulose film is 0.1 mm to 1 mm.

3. The flexible gel actuator with impact resistance and stimulus responsiveness according to claim 1, characterized in that: Poly(3,4-ethylenedioxythiophene)-polystyrene sulfonic acid is also added to the PAA hydrogel to improve the conductive property of the hydrogel.

4. The method for preparing a flexible gel actuator having impact resistance and stimulus responsiveness according to claim 1, characterized in that: The following steps are involved: S1. Prepare acrylic acid AA, ammonium persulfate APS, N,N′-methylenebisacrylamide MBA, poly(3,4-ethylenedioxythiophene)-polystyrene sulfonic acid, metal chloride and bacterial cellulose membrane; S2, dissolving APS, MBA and poly(3,4-ethylenedioxythiophene)-polystyrene sulfonic acid in AA and H2O in a certain proportion, and forming a pre-gel solution by magnetic stirring; S3, pouring the pre-gel solution into the mold where the bacterial cellulose membrane has been placed, copolymerizing at 60°C for 1 hour to form a preliminary composite hydrogel; S4, immersing the initially formed composite hydrogel in a solution containing metal ions to enhance the structure of the hydrogel through metal coordination; S5. Wash the composite hydrogel to remove excess metal ions and obtain the final flexible gel actuator.

5. The method for preparing a flexible gel actuator having impact resistance and stimulus responsiveness according to claim 5, characterized in that: The concentration of the metal ion solution is 0.5 M, and the treatment time is 30 minutes to 60 minutes.

6. The method for preparing a flexible gel actuator having impact resistance and stimulus responsiveness according to claim 5, characterized in that: The cleaning solution used in the cleaning step is deionized water, and the cleaning times are no less than 3 times to ensure that the excess metal ions are completely removed.

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