Reed inner membrane hydrogel composite bionic driving material constructed based on ink-jet printing patterning and preparation method of reed inner membrane hydrogel composite bionic driving material

Abstract

The invention discloses a preparation method for constructing a reed inner membrane hydrogel composite bionic driving material based on ink-jet printing patterning. The preparation method comprises the following steps: performing ink-jet printing treatment on a reed inner membrane; the preparation method comprises the following steps: adding N-isopropylacrylamide, N, N-methylene acrylamide and 2-hydroxy-4 '-(2-hydroxyethoxy)-2-methyl propiophenone into a nano clay aqueous solution, and mixing to obtain a hydrogel pre-polymerized solution; and placing the ink-jet printed reed inner membrane on a glass sheet, adding the hydrogel prepolymerization liquid, covering and sealing the glass sheet, placing the glass sheet in ice water, and carrying out photopolymerization to obtain the reed inner membrane hydrogel composite bionic driving material. Pigment ink is printed on the surface of the natural reed inner film by an ink-jet printer for patterning, then the pigment ink and the poly (N-isopropylacrylamide) hydrogel quickly form a firm mechanical interlocking structure, the binding force is high, and the method is simple; and the driving material has excellent photo-thermal conversion efficiency, mechanical property and pattern construction capability, so that rapid driving, super-power driving force and various complex bionic driver designs are realized.

Description

Technical Field

[0001] The present invention relates to the field of intelligent hydrogel materials, and in particular to a reed inner membrane hydrogel composite bionic driving material constructed based on inkjet printing patterning and a preparation method thereof. Background Art

[0002] Smart hydrogels are functional materials that contain a large amount of water. They can change in volume, color or phase when faced with changes in the environment (temperature, pH, light, electric field, magnetic field, chemical substances, etc.). Toyoichi Tanaka et al. at the Massachusetts Institute of Technology first developed smart hydrogels in 1996. However, most smart hydrogels have simple deformations, and the hydrogel actuators developed based on smart hydrogels have a single driving mode, which greatly limits their application range.

[0003] With the development of science and technology, researchers' research on smart hydrogels has evolved from simple volume expansion / contraction to the ability to achieve various complex drives. Smart-driven hydrogels have become one of the most promising new bionic smart materials in recent years. Among them, photothermal responsive hydrogels are favored by people because of their remote controllability. When photothermal responsive hydrogels are irradiated with near-infrared light, the temperature of the hydrogel in the spot area will rise in a short period of time, causing the gel morphology to change, thereby realizing the complex drive of photothermal responsive hydrogels. For example, Chinese patent CN201910654774.9 discloses a multifunctional light-driven low-temperature resistant double network hydrogel and its preparation method and application. It uses polyacrylamide / sodium alginate-based double network hydrogel / CaCl2 / CNTs network composite hydrogel to undergo photoresponsive deformation. Under near-infrared light irradiation, it can perform unilateral and bilateral bending, wandering, bionic hand grasping and transporting objects and other multifunctional deformations, which are expected to be applied to soft gripping robots, light-driven soft clamps, sensors and wearable devices.

[0004] However, existing intelligent composite hydrogels have problems such as slow driving speed or poor mechanical strength, and most of the designed bionic actuators are spliced ​​together, resulting in relatively simple driving behaviors, but the preparation process is relatively complicated and difficult to mass produce. Moreover, the premise for the existing intelligent composite hydrogels to produce complex driving behaviors is based on the special structure of the composite hydrogel (double-layer structure, oriented structure, etc.), and complex driving behaviors can only occur under specific circumstances, thus limiting their application.

[0005] Therefore, it is necessary to develop a reed inner membrane hydrogel composite bionic driving material based on inkjet printing patterning. Summary of the invention

[0006] In view of this, the present invention provides a preparation method of reed inner membrane hydrogel composite bionic driving material based on inkjet printing patterning to solve the problems of slow driving speed or single driving behavior of existing hydrogel composite bionic driving materials.

[0007] The present invention adopts a preparation method of reed inner membrane hydrogel composite bionic driving material based on inkjet printing patterning, which comprises the following steps:

[0008] S101 performs inkjet printing on the reed inner membrane according to a preset pattern, and obtains the inkjet printed reed inner membrane after drying;

[0009] S102: adding N-isopropylacrylamide, N,N-methyleneacrylamide and 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylpropiophenone to the nanoclay aqueous solution and mixing them evenly to obtain a PNIPAM hydrogel prepolymer solution;

[0010] S103: placing the inkjet-printed reed inner membrane prepared in step S101 on a quartz glass sheet, then infiltrating the inkjet-printed reed inner membrane with the PNIPAM hydrogel prepolymer prepared in step S102 and flattening it, then placing a U-shaped silicone rubber on the inkjet-printed reed inner membrane, then adding the PNIPAM hydrogel prepolymer, and after the prepolymer completely penetrates into one side of the inkjet-printed reed inner membrane, covering it with a quartz glass sheet, photopolymerizing it under an ultraviolet lamp, and soaking it in a large amount of deionized water to remove impurities to obtain a reed inner membrane hydrogel composite bionic driving material.

[0011] Preferably, in step S102, the nanoclay aqueous solution 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-methyleneacrylamide added is 2.5 mg, and the amount of 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylpropiophenone added is 3.5 mg.

[0013] Preferably, in step S103, the wavelength of the ultraviolet lamp is 365nm, 12.8mW / cm 2 .

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

[0015] Preferably, in step S103, the U-shaped silicone rubber inner groove is 20 mm*40 mm, and the amount of PNIPAM hydrogel prepolymer solution used is 400 μl.

[0016] The invention provides a method for preparing a reed inner membrane hydrogel composite bionic driving material based on inkjet printing patterning. The pigment ink is printed on the surface of the natural reed inner membrane by an inkjet printer, and then the inkjet printed reed inner membrane and poly N-isopropylacrylamide hydrogel are quickly formed into a strong mechanical interlocking structure, which has strong bonding force, simple method, and no interlayer peeling phenomenon occurs during the driving process. The method can be used to arbitrarily construct various complex patterned hydrogel bionic actuators, and realize complex bionic driving behaviors under near-infrared irradiation.

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

[0018] Furthermore, the reed inner membrane hydrogel composite bionic driving material prepared by this method will bend under the irradiation of a surface light source, and will bend under the irradiation of a point light source, providing more driving modes for the biomass composite hydrogel.

[0019] Furthermore, the inkjet printing method of the present invention can be used to produce smart hydrogels with different patterns, which not only exhibit remote and precise controllable characteristics, but also provide more complex spiral driving behaviors, especially convenient and quick programmable design of various bionic patterns and preparation of corresponding smart hydrogel bionic actuators, and realization of corresponding bionic driving behaviors. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 A schematic diagram of the preparation process of a reed inner membrane hydrogel composite bionic driving material constructed based on inkjet printing patterning of the present invention;

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

[0022] Figure 3 This is the test result of the photothermal conversion efficiency of the reed inner membrane hydrogel composite bionic driving material;

[0023] Figure 4 This is a graph showing the mechanical properties test results of the reed inner membrane hydrogel composite bionic driving material;

[0024] Figure 5 This is a test diagram of the bending performance of the reed inner membrane hydrogel composite bionic driving material;

[0025] Figure 6 This is a test diagram of the bending performance of the reed inner membrane hydrogel composite bionic driving material;

[0026] Figure 7 Schematic diagram of the complex driving behavior of a bionic actuator with a stripe pattern under near-infrared light;

[0027] Figure 8 Schematic diagram of the complex driving behavior of a bionic actuator in the shape of a "bionic hand" pattern under near-infrared light;

[0028] Fig. 9 Schematic diagram of the complex driving behavior of a bionic actuator with a "bionic octopus" pattern under near-infrared light;

[0029] Fig.10 Schematic diagram of the complex driving behavior of a bionic actuator in the shape of a "bionic eagle claw" pattern under near-infrared light; DETAILED DESCRIPTION

[0030] The principles and features of the present invention are described below in conjunction with the accompanying drawings. The examples given are only used to explain the present invention and are not used to limit the scope of the present invention.

[0031] The pigment ink involved in the embodiment of the present invention (Huaxia Caimo Epson advanced pigment ink BK originally equipped with 1805L8058 Epson printer) was purchased from Guangzhou Zhenghe Electronic Technology Co., Ltd., the reed inner film (thickness of 10 μm) was purchased from Hangzhou Chuangfeng Musical Instruments Co., Ltd., and other chemical reagents and raw materials were purchased from regular companies.

[0032] Example 1: Reference Figure 1 A method for preparing a reed inner membrane hydrogel composite bionic driving material based on inkjet printing patterning comprises the following steps:

[0033] S101 Inkjet printing of reed inner membrane: first print a preset frame on A4 paper, use tape to stick the reed inner membrane with a thickness of 10 μm on the frame of A4 paper, print black pigment ink on the surface of the reed inner membrane in the form of a pattern based on inkjet printing technology, place the printed reed inner membrane in a fume hood for 4 hours, then place it under an infrared lamp for 2 hours to completely dry, and then 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 solution: 10 mg of nanoclay (XLS) was weighed and added to 1 mL of deionized water to prepare an XLS aqueous solution. Then, 100 mg of N-isopropylacrylamide (NIPAM), 2.5 mg of N,N-methyleneacrylamide (BIS) and 3.5 mg of 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylpropiophenone (I-2959) were added to the XLS aqueous solution in sequence and placed in a vortex machine for mixing for 3 minutes for later use;

[0035] S103 Preparation of IRM / PNIPAM composite hydrogel (IP hydrogel): The inkjet-printed reed inner membrane prepared in step S101 was placed on a quartz glass sheet, then infiltrated with PNIPAM hydrogel prepolymer solution and flattened, and then a U-shaped silicone rubber with a thickness of 150 μm (the empty groove is 20 mm*40 mm) was placed on the inkjet-printed reed inner membrane, and then PNIPAM hydrogel prepolymer solution (400 μl) was added. After the prepolymer solution completely penetrated into one side of the inkjet-printed reed inner membrane, a quartz glass sheet was covered, sealed with a clip, and placed in ice water, and then illuminated under a UV lamp (365 nm, 12.8 mW / cm 2 The obtained composite hydrogel was immersed in a large amount of deionized water for 2 days to remove the unreacted monomers and other impurities in the hydrogel to obtain the IRM / PNIPAM composite hydrogel, and the bionic actuator was obtained by cutting technology.

[0036] In other embodiments, the reed inner membrane may also be replaced by other high-strength plant fiber membranes.

[0037] Example 2: Characterization and performance testing of the IRM / PNIPAM composite hydrogel prepared in Example 1:

[0038] (1) SEM and EDS-mapping tests were performed on the IRM / PNIPAM composite hydrogel prepared in Example 1:

[0039] Through Figure 2 The results of scanning electron microscopy showed that the IP smart hydrogel has a double-layer structure, with the upper layer being IRM and the lower layer being PNIPAM hydrogel. There is a strong bonding interface between the IRM and PNIPAM layers. It may be that the IRM is hydrophilic, and the PNIPAM hydrogel can penetrate into the IRM and form a strong mechanical interlocking structure with the rough surface of the reed inner membrane. Furthermore, through EDS-mapping tests on the IP smart hydrogel, Si and Mg elements were found in the cross-section of the IP smart hydrogel. The Si and Mg elements come from the nanoclay in the PNIPAM hydrogel, indicating that the PNIPAM hydrogel has successfully penetrated into the bottom side of the reed inner membrane and formed a strong structure.

[0040] (2) Test on the photothermal conversion efficiency of the IRM / PNIPAM composite hydrogel prepared in Example 1:

[0041] like Figure 3 As shown in the results of a, under the same light spot (30 cm away from the test sample), the temperature of the inkjet printed reed inner film increases with the increase of light power. From 0s to 70s, 1W / cm 2 When the light power is 7.5W / cm2 When the temperature reaches 31.2° in 10 seconds, it rises to 64.9° in 70 seconds. Figure 3 As shown in the results of Figure 2, with the increase of light power, the heating rate and final temperature of the IP smart hydrogel increased. This shows that the IP smart hydrogel has excellent photothermal conversion efficiency. In another embodiment, the IP smart hydrogel prepared by using red, green, and blue black pigment inks instead of black pigment ink, respectively, under the light power of 7.5W / cm 2 When the temperature required for driving is reached, it can be shown that the color pigment ink can also provide a certain light-to-heat conversion efficiency for the natural biomass reed film, but the driving rate is not as good as that of the black pigment ink.

[0042] (3) Mechanical properties test of the IRM / PNIPAM composite hydrogel prepared in Example 1:

[0043] 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 of 23.8 KPa. That is, the tensile strength of the IP smart hydrogel prepared by IRM is 113 times higher than that of the pure PNIPAM hydrogel, providing a better driving force for the IP smart hydrogel.

[0044] (4) Study on the bending properties of the IRM / PNIPAM composite hydrogel prepared in Example 1:

[0045] First, a strip of IP smart hydrogel with a size of 12 mm in length, 3 mm in width and 0.16 mm in thickness was selected as the experimental sample. 2 Near-infrared light, under the full irradiation of near-infrared light, the long strip IP smart hydrogel can bend quickly from 0° to 283° in 3.74s ( Figure 5 a). After the near-infrared light is removed, the IP smart hydrogel will continue to return to its initial state within 77.9 seconds ( Figure 5 b) Compared with the photothermal actuation time of PNIPAM smart hydrogel, which takes tens of seconds to several minutes, the IP smart hydrogel of the present invention completed a 283° bend within 4 seconds. This shows that the actuation speed and recovery speed of PNIPAM hydrogel are significantly improved, and it can rise above LCST in a short time, so that the hydrogel can shrink rapidly and produce actuation behavior.

[0046] (5) Study on the bending properties of the IRM / PNIPAM composite hydrogel prepared in Example 1:

[0047] A strip of IP smart hydrogel with a size of 12 mm in length, 1 mm in width and 0.16 mm in thickness was selected as the experimental sample, and then the applied strength was 12 W / cm2 Under the irradiation of near-infrared point light source, the long composite hydrogel only needs 1.75s ( Figure 6 a), when the point light source is removed, the long composite hydrogel recovers from 90° to its initial shape within 64 s ( Figure 6 b). First, make sure the diameter of the point light source is 1mm. When changing the near-infrared light power, increase the distance to keep the spot size consistent. 2 When the IRM temperature rise rate is relatively slow, that is, the PNIPAM hydrogel shrinkage rate is also relatively slow. It takes 2.69s for the long strip IP smart hydrogel to bend from 0° to 90°. When the near-infrared light source intensity is 60W / cm 2 When the temperature of IRM rises sharply, the shrinkage rate of PNIPAM hydrogel is greatly accelerated, and the strip IP smart hydrogel only needs 0.44s ( Figure 6 c), indicating that controlling the spot size and intensity of near-infrared light can achieve bending and curvature.

[0048] (6) Study on the spiral driving behavior of the IRM / PNIPAM composite hydrogel prepared in Example 1

[0049] like Figure 7 , a stripe pattern shape was designed based on programmable inkjet printing technology, in which the width of the black printed area (width is 0.7mm) is twice that of the white unprinted area (width is 0.35mm), in order to provide more driving force. Based on inkjet printing technology, black pigment ink is printed onto the inner membrane of the reed, and the programmable IP smart hydrogel is designed to have a black stripe pattern with an angle of 0°, 30°, 45°, 60°, and 90° to the horizontal direction, and a length of 15mm and a width of 2.8mm. When near-infrared light (808nm, 5.2W / cm 2 When the light intensity is high (high), the programmable IP smart hydrogel will bend or spiral due to local contraction. When the angle between the black stripe pattern and the length direction of the hydrogel is 0°, the black area gel shrinks, so that the IP smart hydrogel will bend along the width direction. When the angle between the black stripe pattern and the length direction of the hydrogel is 90°, the IP smart hydrogel bends along the length direction. When the angle between the black stripe pattern and the length direction of the hydrogel is between 0° and 90°, the IP smart hydrogel will undergo spiral driving behavior, and as the angle increases, the pitch decreases, indicating that this material can achieve complex spiral driving behavior.

[0050] Example 3: The preparation method of Example 1 is used to construct bionic actuators with different patterns to achieve complex driving behaviors.

[0051] (1) Figure 8, a "bionic hand" pattern was designed based on the programmable technology of inkjet printing, and this pattern was accurately printed on the surface of the reed inner membrane using an inkjet printer to prepare a double-layer PIP smart hydrogel, and the "bionic hand" was cut out using cutting technology. In order for the "bionic hand" to accurately imitate the various movements of the hand, black stripe patterns were designed at each knuckle, so that various driving behaviors of the "bionic hand" can be remotely and accurately controlled. From the driving behavior of the programmable PIP smart hydrogel bionic actuator, it can be seen that when near-infrared light is applied, the black pattern area causes the PNIPAM hydrogel to shrink due to its excellent photothermal conversion efficiency, thereby inducing driving behavior. When near-infrared light from a surface light source is applied, the "bionic hand" is covered by light, and the temperature of the black pattern area gradually increases with time, thereby causing the volume of the PNIPAM hydrogel in this area to shrink. Since the volume of the unprinted area does not change, the contraction of the PNIPAM hydrogel in the black pattern area is limited, thereby inducing bending driving behavior. When the two black stripe pattern areas at the knuckles on the fingers shrink at the same time, bending driving behavior is exhibited.

[0052] In addition, "bionic octopus" (such as Fig. 9 ) and "Bionic Eagle Claw" ( Fig.10 ) and other bionic drivers, which can imitate biological movement behavior and realize their bionic driving behavior under the remote and precise control of near-infrared light. After testing, the "bionic eagle claw" has a super-high power driving force and can lift objects more than 70 times its own weight. In addition, the inkjet color printing technology of the present invention can be used to design different bionic drivers. First, a blue butterfly, an orange dragonfly, and a red water lily are designed. When near-infrared light is applied, the butterfly shows a driving behavior of flapping its wings, the dragonfly can independently flap its wings, and the water lily shows a driving process of petal closure. Therefore, the simple preparation method and excellent performance make it have broad application prospects in the fields of soft bionic drivers, soft robots, etc.

[0053] In summary, the preparation method of the reed inner membrane hydrogel composite bionic driving material based on inkjet printing patterning provided by the present invention uses an inkjet printer to print pigment ink on the surface of the natural reed inner membrane, and the inkjet printed reed inner membrane can quickly form a strong mechanical interlocking structure with the poly N-isopropylacrylamide hydrogel, which has strong bonding force, simple method, and no interlayer peeling phenomenon occurs during the driving process. Furthermore, the present method is convenient for designing various complex patterned hydrogel bionic actuators, and realizing complex bionic driving behaviors under near-infrared irradiation.

[0054] Furthermore, the reed inner membrane hydrogel composite bionic 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 (can lift objects more than 70 times its own weight).

[0055] Furthermore, the reed inner membrane hydrogel composite bionic driving material prepared by this method will bend under the irradiation of a surface light source, and will bend under the irradiation of a point light source, providing more driving modes for the biomass composite hydrogel.

[0056] Furthermore, the inkjet printing method of the present invention can realize smart hydrogels with different patterns, which not only exhibit remote precise controllable characteristics, but also provide more complex spiral driving behaviors. In particular, various bionic patterns can be easily and quickly programmed and the corresponding smart hydrogel bionic actuators can be prepared, and the corresponding bionic driving behaviors can be realized.

[0057] 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 in the scope of protection of the present invention.

Claims

1. A method for preparing a reed inner membrane hydrogel composite bionic driving material based on inkjet printing patterning, characterized in that: The following steps are involved: S101 performs inkjet printing on the reed inner membrane according to a preset pattern, and obtains the inkjet printed reed inner membrane after drying; S102: adding N-isopropylacrylamide, N,N-methyleneacrylamide and 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylpropiophenone to the nanoclay aqueous solution and mixing them evenly to obtain a PNIPAM hydrogel prepolymer solution; S103: placing the inkjet-printed reed inner membrane prepared in step S101 on a quartz glass sheet, then infiltrating the inkjet-printed reed inner membrane with the PNIPAM hydrogel prepolymer prepared in step S102 and flattening it, then placing a U-shaped silicone rubber on the inkjet-printed reed inner membrane, then adding the PNIPAM hydrogel prepolymer, and after the prepolymer completely penetrates into one side of the inkjet-printed reed inner membrane, covering it with a glass sheet for light polymerization, and soaking it in a large amount of deionized water to remove impurities to obtain a reed inner membrane hydrogel composite bionic driving material.

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

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

4. The method for preparing a reed inner membrane hydrogel composite bionic driving material based on inkjet printing patterning according to claim 1, characterized in that: In the step S103, the wavelength of the ultraviolet lamp is 365nm, 12.8mW / cm 2 .

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

6. The method for preparing a reed inner membrane hydrogel composite bionic driving material based on inkjet printing patterning according to claim 1, characterized in that: In the step S103, the U-shaped silicone rubber inner groove is 20 mm*40 mm, and the amount of PNIPAM hydrogel prepolymer solution used is 400 μl.

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

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