A flexible gel actuator with impact resistance and stimulus responsiveness and preparation method thereof

Abstract

The present invention discloses a flexible gel actuator with impact resistance and stimulus responsiveness, comprising: a support layer composed of a bacterial cellulose membrane, which provides structural support; and a response layer composed of a polyacrylic acid (PAA) hydrogel containing metal ion coordination bonds, which is capable of responding to external stimuli. The support layer and the response layer are interconnected by hydrogen bonds, and the response layer is capable of achieving rapid self-deformation and shape memory through the coordination of metal ions and carboxyl groups. The flexible gel actuator with impact resistance and stimulus responsiveness provided by the present invention has both good stimulus responsiveness and 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 robotics 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 fields of biomedicine, environmental governance, and engineering technology 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, and 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 are unable to 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

[0006] 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.

[0007] Technical Solution

[0008] To solve the above technical problems, the present invention provides a technical solution: a flexible gel actuator with impact resistance and stimulus responsiveness, comprising:

[0009] The support layer, composed of bacterial cellulose membrane, provides structural support;

[0010] The response layer is composed of polyacrylic acid (PAA) hydrogel containing metal ion coordination bonds and can respond to external stimuli;

[0011] 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 between metal ions and carboxyl groups.

[0012] As an improvement, the thickness of the bacterial cellulose membrane is 0.1 mm to 1 mm.

[0013] As an improvement, poly(3,4-ethylenedioxythiophene)-polystyrene sulfonic acid is further added to the PAA hydrogel to improve the conductive properties of the hydrogel.

[0014] As an improvement, a method for preparing a flexible gel actuator with impact resistance and stimulus responsiveness includes the following steps:

[0015] 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;

[0016] 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;

[0017] S3, pouring the pre-gel solution into the mold with the bacterial cellulose membrane placed therein, and copolymerizing at 60°C for 1 hour to form a preliminary composite hydrogel;

[0018] S4, immersing the initially formed composite hydrogel in a solution containing metal ions to enhance the structure of the hydrogel through metal coordination;

[0019] S5. Wash the composite hydrogel to remove excess metal ions and obtain the final flexible gel actuator.

[0020] As an improvement, the concentration of the metal ion solution is 0.5 M, and the treatment time is 30 minutes to 60 minutes.

[0021] 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

[0022] The advantages of the present invention compared with the prior art are:

[0023] The flexible gel actuator provided by the present invention forms an integral structure by combining a bacterial cellulose membrane as a support 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 the heterogeneous material; 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 ensure that the PAA layer and the BC layer have stable and excellent interlayer bonding force, preventing interface degradation. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a schematic structural diagram of a flexible gel actuator with impact resistance and stimulus responsiveness according to the present invention.

[0025] Figure 2 This is a flow chart of a method for preparing a flexible gel actuator with impact resistance and stimulus responsiveness according to the present invention.

[0026] Figure 3 This is a gel stretching test diagram of a flexible gel actuator with impact resistance and stimulus responsiveness of the present invention.

[0027] 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.

[0028] Figure 5 This is a puncture test diagram of a flexible gel actuator with impact resistance and stimulus responsiveness according to the present invention.

[0029] 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

[0030] 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

[0031] like Figure 1 As shown, a flexible gel actuator with impact resistance and stimulus responsiveness comprises:

[0032] A support layer, composed of a bacterial cellulose membrane, provides structural support, wherein the thickness of the bacterial cellulose membrane is 0.1 mm to 1 mm;

[0033] The response layer is composed of a polyacrylic acid (PAA) hydrogel containing metal ion coordination bonds and is capable of responding to external stimuli. The PAA hydrogel is also added with poly(3,4-ethylenedioxythiophene)-polystyrene sulfonic acid to improve the conductivity of the hydrogel.

[0034] 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 between metal ions and carboxyl groups. Example

[0035] like Figure 2 The method for preparing a flexible gel actuator having impact resistance and stimulus responsiveness comprises the following steps:

[0036] 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;

[0037] 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;

[0038] S3, pouring the pre-gel solution into the mold with the bacterial cellulose membrane placed therein, and copolymerizing at 60°C for 1 hour to form a preliminary composite hydrogel;

[0039] 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;

[0040] 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.

[0041] Working principle of the present invention:

[0042] Structural connection: The bacterial cellulose membrane and PAA hydrogel are connected to each other through hydrogen bonds to form an integral structure.

[0043] 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 in the same medium, thereby effectively improving the damage resistance and stress concentration resistance of heterogeneous materials.

[0044] 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.

[0045] Shape recovery: Through the coordination effect 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 dissociate, which weakens its ability to temporarily fix the shape, resulting in shape recovery.

[0046] Conductive properties: The added PEDOT:PSS significantly improved the conductive properties of the hydrogel, enabling it to respond quickly under electrical stimulation.

[0047] The following are the performance test experiments of the present invention, specifically including tensile test, puncture test and impact test:

[0048] 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 PAA hydrogel toughness 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%.

[0049] like Figure 4 As shown in the tensile test of the hydrogels made of PBC, PAA and BC, the fracture energy of the PBC hydrogel is 289 J / m 2 The PAA hydrogel fracture energy is 44.83 J / m 2 .

[0050] like Figure 5As shown in FIG, 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.

[0051] 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.

[0052] We propose a scalable and versatile engineering strategy for structurally intact hydrogel actuators, which exhibit excellent impact resistance and enable ion-triggered programmable deformation. Notably, we demonstrate that in situ polymerization of the hydrogel on a cellulose scaffold modulates structural integrity through the synergistic effects of highly crystalline cellulose domains and abundant hydrogen bonds in the matrix, resulting in excellent interfacial stability to prevent stress concentration, significantly outperforming PAA-based hydrogels reported in the literature. The hydrogel also exhibits exceptional bending stability (50,000 bending cycles), toughness (375.53 kJ / m³), and puncture resistance (4.42 N), particularly exhibiting outstanding mechanical properties in terms of tear resistance (289 J / m²). This demonstrates the significant advantages of the bilayer heterogeneous hydrogel prepared using this approach.

[0053] Secondly, the asymmetric deformation behavior of the soft hydrogel actuator can be quantitatively and reversibly adjusted by 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 by 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 smart actuator structural design. 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.

[0054] In summary, the flexible gel actuator prepared by the above method has broad application prospects in soft robots, smart wearable devices, biomedical devices and other fields. It can achieve precise control and efficient response, and provides new ideas and solutions for the development of related technologies.

[0055] It should be noted that, in this document, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that includes a list of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus.

[0056] While 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 these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

[0057] The present invention and its embodiments are described above. This 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 a person skilled in the art is inspired by this and, without departing from the purpose of the present invention, designs structures and embodiments similar to this technical solution without inventiveness, they shall fall within the scope of protection of the present invention.

Claims

1. A flexible gel actuator with 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 between metal ions and carboxyl groups; The preparation method of the flexible gel actuator 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 stirring; S3, pouring the pre-gel solution into the mold where the bacterial cellulose membrane has been placed, copolymerizing to form a preliminary composite hydrogel; S4, immersing the initially formed composite hydrogel in a solution containing metal chloride to strengthen 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.

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 method for preparing a flexible gel actuator with 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, and 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 chloride to strengthen 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.

4. The method for preparing a flexible gel actuator with impact resistance and stimulus responsiveness according to claim 3, characterized in that: The concentration of the metal chloride is 0.5 M, and the treatment time is 30 to 60 minutes.

5. The method for preparing a flexible gel actuator with impact resistance and stimulus responsiveness according to claim 3, 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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