A biomimetic driving material based on inkjet printing patterned reed inner membrane hydrogel composite and its preparation method

Abstract

This invention discloses a method for preparing a biomimetic actuating material based on inkjet printing patterned construction of a reed inner membrane hydrogel composite. The method includes inkjet printing a reed inner membrane; adding N-isopropylacrylamide, N,N-methylenebisacrylamide, and 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylphenylacetone to an aqueous solution of nano-clay to obtain a hydrogel prepolymer; placing the inkjet-printed reed inner membrane on a glass slide, adding the hydrogel prepolymer, covering and sealing it, and then placing it in ice water for photopolymerization to obtain the reed inner membrane hydrogel composite biomimetic actuating material. This invention uses an inkjet printer to print pigment ink onto the surface of a natural reed inner membrane for patterning, and then rapidly forms a strong mechanical interlocking structure with poly(N-isopropylacrylamide) hydrogel, resulting in strong bonding. The method is simple, and the actuating material exhibits excellent photothermal conversion efficiency, mechanical properties, and patterning capabilities, thereby enabling rapid actuation, ultra-high power actuation, and various complex biomimetic actuator designs.

Description

Technical Field

[0001] This invention relates to the field of smart hydrogel materials, and in particular to a biomimetic driving material based on inkjet printing patterned reed inner membrane hydrogel composite and its preparation method. Background Technology

[0002] Smart hydrogels are a class of functional materials containing a large amount of water that can change in volume, color, or phase in response to changes in the environment (temperature, pH, light, electric field, magnetic field, chemical substances, etc.). Toyoichi Tanaka et al. at MIT first developed smart hydrogels in 1996. However, most smart hydrogels have simple deformation characteristics, and the actuation methods of hydrogel actuators developed based on smart hydrogels are limited, which greatly restricts their application range.

[0003] With the development of technology, researchers' research on smart hydrogels has evolved from simple volume expansion / contraction to the ability to achieve various complex actuations. Smart actuated hydrogels have become one of the most promising biomimetic smart materials in recent years. Among them, photothermal responsive hydrogels are favored due to their remote controllability. Under near-infrared light irradiation, the temperature of the hydrogel in the light spot area rises in a short time, causing changes in the gel morphology and thus achieving complex actuation. For example, Chinese patent CN201910654774.9 discloses a multifunctional light-driven low-temperature resistant dual-network hydrogel, its preparation method, and its applications. It utilizes a polyacrylamide / sodium alginate-based dual-network hydrogel / CaCl2 / CNTs network composite hydrogel to undergo photoresponsive deformation. Under near-infrared light irradiation, it can perform multifunctional deformations such as unilateral and bilateral bending, walking, and bionic hand grasping and transporting objects. It is expected to be applied in fields such as soft gripping robots, light-driven soft grippers, sensors, and wearable devices.

[0004] However, existing smart composite hydrogels suffer from slow actuation speed and poor mechanical strength. Furthermore, most of the designed biomimetic actuators are assembled from components, resulting in relatively simple actuation behaviors, while the fabrication process is complex and difficult to mass-produce. Moreover, the complex actuation behaviors of existing smart composite hydrogels are predicated on their special structures (bilayer structures, oriented structures, etc.), meaning these complex behaviors only occur under specific conditions, thus limiting their applications.

[0005] Therefore, it is necessary to develop a biomimetic driving material based on a hydrogel composite of reed inner membranes constructed using inkjet printing patterning. Summary of the Invention

[0006] In view of this, the present invention provides a method for preparing a hydrogel composite biomimetic driving material based on inkjet printing patterned construction of reed inner membrane, which solves the problems of slow driving speed or simple driving behavior of existing hydrogel composite biomimetic driving materials.

[0007] This invention employs a method for preparing a biomimetic driving material based on inkjet printing to pattern the hydrogel composite of reed inner membrane, comprising the following steps:

[0008] S101 prints the inner membrane of the reed using inkjet printing according to a preset pattern, and obtains the inkjet-printed inner membrane of the reed after drying.

[0009] S102 was prepared by adding N-isopropylacrylamide, N,N-methylenebisacrylamide and 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylphenylacetone to an aqueous solution of nano-clay and mixing them evenly to obtain PNIPAM hydrogel prepolymer.

[0010] In step S103, the inkjet-printed reed inner membrane prepared in step S101 is placed on a quartz glass slide. Then, the inkjet-printed reed inner membrane is soaked in the PNIPAM hydrogel prepolymer prepared in step S102 and flattened. Next, a U-shaped silicone rubber is placed on the inkjet-printed reed inner membrane, and then the PNIPAM hydrogel prepolymer is added. After the prepolymer has completely penetrated one side of the inkjet-printed reed inner membrane, the quartz glass slide is covered and polymerized under ultraviolet light. After soaking in a large amount of deionized water to remove impurities, the reed inner membrane hydrogel composite biomimetic driving material is obtained.

[0011] Preferably, in step S102, the aqueous solution of nano-clay has a mass fraction of 1 wt% and a volume of 1 mL.

[0012] Preferably, in step S102, the amount of N-isopropylacrylamide added is 100 mg, the amount of N,N-methylenebisacrylamide added is 2.5 mg, and the amount of 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylphenylacetone added is 3.5 mg.

[0013] Preferably, in step S103, the wavelength of the ultraviolet lamp is 365nm and the wavelength is 12.8mW / cm2.

[0014] Preferably, in step S103, the photopolymerization time is 30 min.

[0015] Preferably, in step S103, the inner groove of the silicone rubber in the shape of a square is 20mm*40mm, and the amount of PNIPAM hydrogel prepolymer liquid used is 400μl.

[0016] This invention provides a method for preparing a biomimetic actuating material based on inkjet printing patterned construction of a reed inner membrane hydrogel composite. The method involves using an inkjet printer to print pigment ink onto the surface of a natural reed inner membrane, then rapidly forming a strong mechanical interlocking structure between the inkjet-printed reed inner membrane and poly(N-isopropylacrylamide) hydrogel. This results in strong adhesion, a simple method, and no interlayer delamination during the actuation process. This method can be used to construct various complex patterned hydrogel biomimetic actuators, achieving complex biomimetic actuation behaviors under near-infrared irradiation.

[0017] Furthermore, the reed inner membrane hydrogel composite biomimetic driving material prepared by this method has excellent photothermal conversion efficiency and mechanical properties (2.7 MPa), thereby achieving rapid driving (bending 204° / s, bending 76° / s) and ultra-high power driving force (capable of lifting objects weighing more than 70 times its own weight).

[0018] Furthermore, the reed inner membrane hydrogel composite biomimetic driving material prepared using this method exhibits bending behavior under surface light source irradiation and bending behavior under point light source irradiation, providing more driving mechanisms for biomass composite hydrogels.

[0019] Furthermore, the inkjet printing method of this invention can be used to create smart hydrogels with different patterns, which not only exhibit remote, precise, and controllable characteristics, but also provide more complex spiral driving behaviors. In particular, it allows for the convenient and quick programmable design of various biomimetic patterns and the fabrication of corresponding smart hydrogel biomimetic actuators, thereby realizing the corresponding biomimetic driving behaviors. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the preparation process of a biomimetic driving material based on inkjet printing patterned reed inner membrane hydrogel composite.

[0021] Figure 2 Scanning electron microscope image (a) and EDS-mapping test image (b) of the biomimetic driving material of reed inner membrane hydrogel composite;

[0022] Figure 3 Figure 1 shows the test results of photothermal conversion efficiency of the biomimetic driving material composed of hydrogel composite of reed inner membrane.

[0023] Figure 4 Figure 1 shows the mechanical property test results of the biomimetic driving material composed of hydrogel composite of reed inner membrane.

[0024] Figure 5 Figure 1 shows the bending performance test results of the reed inner membrane hydrogel composite biomimetic driving material.

[0025] Figure 6 Figure showing the bending performance test of the reed inner membrane hydrogel composite biomimetic driving material;

[0026] Figure 7 A schematic diagram of the complex actuation behavior of a striped patterned biomimetic actuator under near-infrared light;

[0027] Figure 8 A schematic diagram illustrating the complex actuation behavior of a bionic actuator in the shape of a "bionic hand" under near-infrared light;

[0028] Figure 9 A schematic diagram of the complex actuation behavior of a biomimetic actuator in the shape of a "bionic octopus" pattern under near-infrared light.

[0029] Figure 10 A schematic diagram of the complex actuation behavior of a biomimetic actuator with a "bionic eagle claw" pattern under near-infrared light. Detailed Implementation

[0030] The principles and features of the present invention are described below with reference to the accompanying drawings. The examples given are only for explaining the present invention and are not intended to limit the scope of the present invention.

[0031] The pigment ink (Huaxia Color Magic Epson Advanced Pigment Ink BK, originally supplied to the 1805L8058 Epson printer) involved in this embodiment of the invention was purchased from Guangzhou Zhenghe Electronic Technology Co., Ltd., the reed inner film (10μm thick) was purchased from Hangzhou Chuangfeng Musical Instrument Co., Ltd., and other chemical reagents and raw materials were purchased from legitimate companies.

[0032] Example 1: Reference Figure 1 A method for preparing a biomimetic driving material based on inkjet printing patterned construction of reed inner membrane hydrogel composite includes the following steps:

[0033] S101 Reed Inner Membrane Inkjet Printing Process: First, print a preset frame on A4 paper. Then, use tape to attach a 10μm thick reed inner membrane to the frame on the A4 paper. Based on inkjet printing technology, print black pigment ink onto the surface of the reed inner membrane. Place the printed reed inner membrane in a fume hood for 4 hours, and then place it under an infrared lamp for 2 hours to dry completely. Finally, remove the inkjet-printed reed inner membrane from the A4 paper to obtain the inkjet-printed reed inner membrane (IRM).

[0034] S102 PNIPAM hydrogel prepolymer: Weigh 10 mg of nano clay (XLS) and add it to 1 mL of deionized water to prepare an XLS aqueous solution. Then, add 100 mg of N-isopropylacrylamide (NIPAM), 2.5 mg of N,N-methylenebisacrylamide (BIS), and 3.5 mg of 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylphenylacetone (I-2959) to the XLS aqueous solution in sequence and mix in a vortex mixer for 3 minutes for later use.

[0035] Preparation of S103 IRM / PNIPAM composite hydrogel (IP hydrogel): The inkjet-printed reed inner membrane prepared in step S101 was placed on a quartz glass slide. Then, PNIPAM hydrogel prepolymer solution was applied and the membrane was flattened. A 150μm thick (20mm*40mm empty groove) U-shaped silicone rubber was placed on the inkjet-printed reed inner membrane. PNIPAM hydrogel prepolymer solution (400μl) was then added. After the prepolymer solution had completely penetrated one side of the inkjet-printed reed inner membrane, the quartz glass slide was covered, and the membrane was sealed with clips and placed in ice water. The membrane was then exposed to UV light (365nm, 12.8mW / cm²). 2 Photopolymerization was carried out for 30 minutes. The resulting composite hydrogel was then soaked in a large amount of deionized water for 2 days to remove unreacted monomers and other impurities, thus obtaining the IRM / PNIPAM composite hydrogel.

[0036] Example 2: Characterization and performance testing of the IRM / PNIPAM composite hydrogel prepared in Example 1:

[0037] (1) SEM and EDS-mapping tests were performed on the IRM / PNIPAM composite hydrogel prepared in Example 1:

[0038] Through such Figure 2 Scanning electron microscopy (SEM) results revealed that the IP smart hydrogel has a bilayer structure: an upper layer of IRM and a lower layer of PNIPAM hydrogel. A strong bonding interface exists between the IRM and PNIPAM layers, likely due to the hydrophilicity of the IRM, allowing the PNIPAM hydrogel to penetrate and form a robust mechanical interlocking structure with the rough reed inner membrane. Furthermore, EDS-mapping analysis of the IP smart hydrogel revealed Si and Mg elements in its cross-section. These Si and Mg elements originated from nano-clay within the PNIPAM hydrogel, indicating that the PNIPAM hydrogel successfully penetrated to the underside of the reed inner membrane and formed a robust structure.

[0039] (2) Photothermal conversion efficiency test of the IRM / PNIPAM composite hydrogel prepared in Example 1:

[0040] like Figure 3 The results show that, under the same illumination spot (30 cm from the test sample), the temperature of the inkjet-printed reed inner membrane increases with increasing illumination power, as does the final temperature. Within the time frame from 0 to 70 seconds, 1 W / cm²... 2 Under a certain light intensity, the temperature rose from 22.2°C to 30.9°C. However, when the light intensity was 7.5 W / cm², the temperature increased. 2 At that time, the temperature reached 31.2°C in 10 seconds and rose to 64.9°C in 70 seconds. For example... Figure 3The results show that the heating rate and final temperature of the IP smart hydrogel both increase with increasing light irradiation power. This indicates that the IP smart hydrogel possesses excellent photothermal conversion efficiency. In another embodiment, IP smart hydrogels prepared using red, green, and blue-black pigment inks instead of black pigment ink, respectively, achieved a higher heating rate and final temperature under a light irradiation power of 7.5 W / cm². 2 At the same time, the required driving temperature can be reached, indicating that colored pigment ink can also provide a certain photothermal conversion efficiency for natural biomass reed membranes, but the driving rate is not as good as that of black pigment ink.

[0041] (3) Mechanical property testing of the IRM / PNIPAM composite hydrogel prepared in Example 1:

[0042] like Figure 4 The results show that the tensile strength of the IP smart hydrogel prepared in Example 1 is 2.7 MPa, which is much higher than the tensile strength of PNIPAM hydrogel (23.8 kPa). That is, the tensile strength of the IP smart hydrogel prepared by IRM is 113 times higher than that of pure PNIPAM hydrogel, providing a better driving force for IP smart hydrogel.

[0043] (4) Study on the bending properties of the IRM / PNIPAM composite hydrogel prepared in Example 1:

[0044] First, a strip-shaped IP smart hydrogel with dimensions of 12 mm in length, 3 mm in width, and 0.16 mm in thickness was selected as the experimental sample. Then, an application strength of 5.2 W / cm² was applied. 2 Under complete near-infrared light irradiation, the elongated IP smart hydrogel can rapidly bend from 0° to 283° in 3.74 seconds. Figure 5 a). Subsequently, when the near-infrared light is removed, the IP smart hydrogel will continuously recover to its initial state within 77.9 seconds. Figure 5 (b) Compared to the PNIPAM smart hydrogel, which requires tens of seconds to several minutes for photothermal actuation, the IP smart hydrogel of this invention completes a 283° bend within 4 seconds. This indicates that the actuation speed and recovery speed of the PNIPAM hydrogel are significantly improved, and can rise above LCST in a short time, causing the hydrogel to contract rapidly and generate actuation behavior.

[0045] (5) Study on the bending properties of the IRM / PNIPAM composite hydrogel prepared in Example 1:

[0046] A strip-shaped IP smart hydrogel with dimensions of 12 mm in length, 1 mm in width, and 0.16 mm in thickness was selected as the experimental sample, and then an application force of 12 W / cm was applied. 2 Under the illumination of a near-infrared spot light source, the long strip of composite hydrogel can change from 0° to 90° in just 1.75 seconds. Figure 6a) When the point light source is removed, the elongated composite hydrogel recovers its initial shape from 90° within 64 seconds. Figure 6 b). First, ensure the diameter of the point light source spot is 1mm. When changing the near-infrared light power, increase the distance to maintain a consistent spot size. When the near-infrared point light source intensity is 6W / cm²... 2 At this time, the IRM temperature rise rate is relatively slow, meaning the PNIPAM hydrogel shrinkage rate is also relatively slow. A long strip of IP smart hydrogel takes 2.69 seconds to bend from 0° to 90°. When the near-infrared spot light source intensity is 60 W / cm²... 2 At that time, the IRM temperature rises sharply, meaning the shrinkage rate of the PNIPAM hydrogel increases significantly; the strip-shaped IP smart hydrogel can be bent from 0° to 90° in just 0.44 seconds. Figure 6 c) This indicates that controlling the size and intensity of the near-infrared light spot can achieve bending and folding.

[0047] (6) Study on the helical driving behavior of the IRM / PNIPAM composite hydrogel prepared in Example 1

[0048] like Figure 7 Based on inkjet printing programmable technology, a striped pattern was designed, where the width of the black printed area (0.7 mm) is twice that of the white unprinted area (0.35 mm), aiming to provide more driving force. Black pigment ink was printed onto the inner membrane of a reed using inkjet printing technology, and a programmable IP smart hydrogel was designed to create black striped patterns with angles of 0°, 30°, 45°, 60°, and 90° to the horizontal, with lengths of 15 mm and widths of 2.8 mm. When near-infrared light (808 nm, 5.2 W / cm²) was applied... 2 Under certain light intensity, the programmable IP smart hydrogel exhibits bending or helical behavior due to localized contraction. When the angle between the black stripe pattern and the hydrogel's length direction is 0°, the gel in the black area contracts, causing the IP smart hydrogel to bend along its width. When the angle between the black stripe pattern and the hydrogel's length direction is 90°, the IP smart hydrogel bends along its length direction. When the angle between the black stripe pattern and the hydrogel's length direction is between 0° and 90°, the IP smart hydrogel exhibits helical behavior, with the pitch decreasing as the angle increases.

[0049] Example 3: Using the preparation method of Example 1, biomimetic actuators with different patterns are constructed to achieve complex driving behavior.

[0050] (1) As Figure 8A "bionic hand" pattern was designed based on inkjet printing programmable technology and precisely printed onto the surface of a reed inner membrane using an inkjet printer to prepare a double-layer PIP smart hydrogel. The "bionic hand" was then cut out using a cutting technique. To enable the "bionic hand" to accurately mimic various hand movements, black stripe patterns were designed at each finger joint, allowing for remote, precise, and controllable actuation of various driving behaviors. The actuation behavior of the programmable PIP smart hydrogel bionic actuator reveals that when near-infrared light is applied, the black pattern area causes the PNIPAM hydrogel to shrink due to its excellent photothermal conversion efficiency, thus triggering the driving behavior. When near-infrared light from a surface light source is applied, the "bionic hand" is covered by the light, and the temperature of the black pattern area gradually increases over time, causing the PNIPAM hydrogel in this area to shrink. Since the volume of the unprinted area does not change, the shrinkage of the PNIPAM hydrogel in the black pattern area is limited, thus triggering bending actuation behavior. When the two black stripe pattern areas at the finger joints shrink simultaneously, bending actuation behavior is exhibited.

[0051] Additionally, "bionic octopuses" (such as...) can be produced. Figure 9 ) and "bionic eagle claw" Figure 10 These biomimetic actuators can mimic biological movement behaviors and achieve biomimetic actuation under precise remote control using near-infrared light. Tests have shown that the "bionic eagle claw" possesses a high-power driving force capable of lifting objects weighing over 70 times its own weight. Furthermore, the inkjet printing technology of this invention can be used to design different biomimetic actuators. Firstly, blue butterflies, orange dragonflies, and red water lilies were designed. When near-infrared light is applied, the butterfly exhibits wing-flapping actuation behavior, the dragonfly demonstrates independent wing-flapping actuation process, and the water lily exhibits petal-closing actuation process. Therefore, the simple fabrication method and excellent performance make it a promising candidate for applications in soft biomimetic actuators, soft robots, and other fields.

[0052] In summary, the preparation method of the biomimetic actuation material based on inkjet printing patterned construction of reed inner membrane hydrogel provided by this invention uses an inkjet printer to print pigment ink onto the surface of natural reed inner membrane. The inkjet-printed reed inner membrane can rapidly form a strong mechanical interlocking structure with poly(N-isopropylacrylamide) hydrogel, exhibiting strong adhesion. The method is simple and does not cause interlayer delamination during the actuation process. Furthermore, this method facilitates the design of various complex patterned hydrogel biomimetic actuators, enabling the realization of complex biomimetic actuation behaviors under near-infrared irradiation.

[0053] Furthermore, the reed inner membrane hydrogel composite biomimetic driving material prepared by this method has excellent photothermal conversion efficiency and mechanical properties, thereby achieving rapid driving (bending 204° / s, bending 76° / s) and ultra-high power driving force (capable of lifting objects weighing more than 70 times its own weight).

[0054] Furthermore, the reed inner membrane hydrogel composite biomimetic driving material prepared using this method exhibits bending behavior under surface light source irradiation and bending behavior under point light source irradiation, providing more driving mechanisms for biomass composite hydrogels.

[0055] Furthermore, the inkjet printing method of this invention can be used to create smart hydrogels with different patterns, which not only exhibit remote, precise, and controllable characteristics, but also provide more complex spiral driving behaviors. In particular, it can conveniently and quickly programmably design various biomimetic patterns and prepare corresponding smart hydrogel biomimetic actuators, and realize corresponding biomimetic driving behaviors.

[0056] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for preparing a biomimetic driving material based on inkjet printing patterned construction of a reed inner membrane hydrogel composite, characterized in that, Includes the following steps: S101 performs inkjet printing on the reed inner membrane according to the preset pattern. The inkjet printer prints pigment ink onto the surface of the natural reed inner membrane, and after drying, the inkjet printed reed inner membrane is obtained. S102 was prepared by adding N-isopropylacrylamide, N,N-methylenebisacrylamide and 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylphenylacetone to an aqueous solution of nano-clay XLS and mixing them evenly to obtain a PNIPAM hydrogel prepolymer. In step S103, the inkjet-printed reed inner membrane prepared in step S101 is placed on a quartz glass slide. Then, the inkjet-printed reed inner membrane is soaked in the PNIPAM hydrogel prepolymer prepared in step S102 and flattened. Next, a U-shaped silicone rubber is placed on the inkjet-printed reed inner membrane, and then the PNIPAM hydrogel prepolymer is added. After the prepolymer has completely penetrated one side of the inkjet-printed reed inner membrane, the quartz glass slide is covered and polymerized under ultraviolet light. After soaking in a large amount of deionized water to remove impurities, the reed inner membrane hydrogel composite biomimetic driving material is obtained.

2. The method for preparing a biomimetic driving material based on inkjet printing patterned construction of reed inner membrane hydrogel composite material according to claim 1, characterized in that, In step S102, the aqueous solution of nano-clay has a mass fraction of 1 wt% and a volume of 1 mL.

3. The method for preparing a biomimetic driving material based on inkjet printing patterned construction of reed inner membrane hydrogel composite material according to claim 1, characterized in that, In step S102, the amount of N-isopropylacrylamide added is 100 mg, the amount of N,N-methylenebisacrylamide added is 2.5 mg, and the amount of 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylphenylacetone added is 3.5 mg.

4. The method for preparing a biomimetic driving material based on inkjet printing patterned construction of reed inner membrane hydrogel composite material according to claim 1, characterized in that, In step S103, the ultraviolet lamp has a wavelength of 365nm and a power of 12.8mW / cm². 2 .

5. The method for preparing a biomimetic driving material based on inkjet printing patterned construction of reed inner membrane hydrogel composite material according to claim 1, characterized in that, In step S103, the photopolymerization time is 30 minutes.

6. The method for preparing a biomimetic driving material based on inkjet printing patterned construction of reed inner membrane hydrogel composite material according to claim 1, characterized in that, In step S103, the inner groove of the silicone rubber in the shape of a square is 20mm*40mm, and the amount of PNIPAM hydrogel prepolymer liquid used is 400μl.

7. A biomimetic driving material based on inkjet printing patterned construction of reed inner membrane hydrogel composite, prepared by the method according to any one of claims 1 to 6.

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