Temperature reversible and cleanable shape memory adhesive material, and method of making and use thereof

Abstract

This invention discloses a temperature-reversible and washable shape memory adhesive material, its preparation method, and its application. The shape memory adhesive material is a crosslinked polymer of octadecyl acrylate, dodecyl acrylate, and UDA. The adhesive material provided by this invention integrates the characteristics of temperature-reversible adhesion, washability, and shape memory. Based on its reversible adhesion function due to its phase change characteristics, it is semi-crystalline below room temperature and exhibits non-stickiness. At skin temperature, it is amorphous and exhibits strong adhesion, thus achieving temperature-reversible adhesion. It is washable, meaning that contaminants can be cleaned without affecting the material's adhesion. It also possesses shape memory properties, allowing it to be used as an adhesive patch for reversible adhesion and reuse in microfluidic chips.

Description

Technical Field

[0001] This invention relates to the field of adhesive material preparation, and more particularly to a temperature-reversible and washable shape memory adhesive material, its preparation method, and its application. Background Technology

[0002] The adhesive layer of flexible wearable devices needs to adhere to the skin, and this layer should possess reversible adhesion properties to adapt to different application scenarios. However, existing adhesive layers, such as double-sided tape and self-adhesive silicone, do not possess reversible adhesion properties, and they require methods such as light pressure to bond to the surface, often resulting in insufficient adhesion. Furthermore, removing the adhesive layer may cause inflammatory reactions, leading to irritation or pain, further exacerbating discomfort during use. Simultaneously, when the adhesive layer is used in combination with a microfluidic chip, existing adhesive materials cannot return to their original shape after deformation, leading to mismatch with the microfluidic chip's liquid inlet channels upon reuse. Moreover, after repeated use, the adhesive layer surface becomes contaminated with pollutants such as sweat and dust, reducing or even eliminating its adhesive ability, rendering the adhesive layer unusable for multiple uses. In addition, many existing wearable strain sensors require an additional adhesive layer beneath the substrate to adhere to human skin, which may lead to inaccurate or untimely capture of many subtle physiological signals. Therefore, strain sensors based on reversible adhesive materials have greater practical value. To address these issues, the required adhesive materials need to possess properties such as reversible adhesion, washability, shape memory, and simple fabrication processes, in order to adapt to different usage scenarios and improve the practicality and comfort of wearable devices. Summary of the Invention

[0003] Addressing the challenges of achieving reversible adhesion and using a single material through simple means in existing technologies, and the inability to simultaneously possess reversible adhesion, washability, and shape memory, the first objective of this invention is to provide a temperature-reversible and washable shape memory adhesive material. The adhesive material provided by this invention integrates temperature-reversible adhesion, washability, and shape memory properties. Its reversible adhesion function is based on its phase change characteristics: it is semi-crystalline below room temperature, exhibiting non-stickiness; at skin temperature, it is amorphous, exhibiting strong adhesion, thus achieving temperature-reversible adhesion; it is washable, allowing it to be cleaned of contaminants without affecting its adhesiveness; and it possesses shape memory properties, enabling reversible adhesion and reuse as an adhesive patch for microfluidic chips.

[0004] The second objective of this invention is to provide a method for preparing a temperature-reversible and washable shape memory adhesive material. The preparation method of this invention is a one-step process, which is simple and controllable.

[0005] The third objective of this invention is to provide an application of a temperature-reversible and washable shape memory adhesive material, which can be used as an adhesive patch in a microfluidic chip to achieve reversible adhesion and repeated use; when applied to a wearable flexible strain sensor, it can be used to detect subtle physiological signals in the human body, as it can better fit the skin, and the obtained signals are accurate and real-time.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] The present invention discloses a temperature-reversible and washable shape memory adhesive material, wherein the shape memory adhesive material is a crosslinked polymer of octadecyl acrylate, dodecyl acrylate and polyurethane diacrylate (UDA), wherein the mass fraction of polyurethane diacrylate (UDA) in the shape memory adhesive material is 15~25%, and the mass ratio of octadecyl acrylate to dodecyl acrylate is 1~1.75.

[0008] The shape memory adhesive material provided by this invention is a crosslinked polymer of octadecyl acrylate and dodecyl acrylate. This invention controls the ratio of octadecyl acrylate to dodecyl acrylate, utilizing dodecyl acrylate with a short alkyl side chain of 12 carbons to lower the phase transition temperature of the adhesive material. This results in a transition temperature slightly lower than skin temperature. Because the material exhibits different states before and after the transition temperature: triggered by skin temperature, the material changes from a semi-crystalline state to an amorphous state, allowing the film to easily flow and adhere to the target surface, forming a smooth and tight bond that is difficult to peel off; subsequently, when the surface temperature is lowered to room temperature, the film changes from an amorphous state to a semi-crystalline state, significantly reducing the adhesion strength and making it easy to detach. Reversible adhesion can be achieved at different temperatures, and the required temperatures are within the human safety range, making it easy to implement. Furthermore, the shape memory adhesive material provided by this invention is itself a cross-linked polymer with a cross-linked network structure. Due to the good flexibility of the polymer molecular chains, the chain segments can rotate and move freely. Above the transition temperature, the material has high resilience, and the resulting adhesive patch has shape memory function. In addition, due to the low adhesion at low temperatures and the adjustment of surface energy and roughness, the surface of this adhesive material has washable properties. After being contaminated with pollutants such as dust and sweat, the surface can be cleaned with water or alcohol without affecting the material's adhesion and shape memory properties, and the material can be reused.

[0009] In this invention, to simultaneously achieve the properties of reversible adhesion, washability, and shape memory, it is necessary to effectively control the raw materials and components. If the proportion of dodecyl acrylate is too large, the phase transition temperature of the material will be too low, and the material will exhibit amorphous adhesion characteristics at room temperature. If crystallization is required, the temperature needs to be lowered further. If the proportion of dodecyl acrylate is too small, the phase transition temperature of the material cannot be effectively reduced, and the material will only exhibit adhesion at a higher temperature. Furthermore, it will be brittle at room temperature and cannot be used effectively. If dodecyl acrylate and polyurethane diacrylate are replaced with other materials, it may not be possible to simultaneously obtain the properties of reversible adhesion, washability, and shape memory, especially the ability to be washed after being contaminated with pollutants without affecting the material's adhesion.

[0010] In a preferred embodiment, the phase transition temperature of the shape memory adhesive material is 28-33℃.

[0011] This invention discloses a method for preparing a temperature-reversible and washable shape memory adhesive material. The method involves mixing octadecyl acrylate, dodecyl acrylate, polyurethane diacrylate (UDA), 2,2-dimethoxy-2-phenylacetophenone (DMPA), and benzophenone (Ben) to obtain a mixed solution. The mixed solution is poured into a mold and placed on a hot platen. A crosslinking polymerization reaction is initiated by ultraviolet light to obtain a crosslinked polymer containing oligomers. The crosslinked polymer containing oligomers is then heat-treated to remove the oligomers. After refrigeration, the material is demolded to obtain the adhesive material.

[0012] The preparation method of the present invention is a simple one-step process. Octadecyl acrylate and dodecyl acrylate are used as crosslinking polymer raw materials, UDA is used as a crosslinking agent, and DMPA and Ben are used as photoinitiators. The mixture is poured into the required mold and free radical copolymerization is initiated by ultraviolet light of a specific wavelength. The adhesive material of the required shape is prepared in one step, and the triggering adhesion temperature is close to the human body temperature. The preparation method is simple and time-saving.

[0013] In this invention, using DMPA and Ben together as photoinitiators can improve initiation efficiency, reduce side reactions and oligomer formation, and increase crosslinking degree, thereby giving the resulting adhesive material superior performance.

[0014] In a preferred embodiment, the mass ratio of octadecyl acrylate to dodecyl acrylate is 1 to 1.75.

[0015] In a preferred embodiment, the amount of UDA added is 15-25% of the total mass of octadecyl acrylate and dodecyl acrylate.

[0016] In a preferred embodiment, the DMPA has a mass fraction of 0.5-1% in the mixed solution, and the Ben has a mass fraction of 0.2-0.5% in the mixed solution.

[0017] The preferred method is ultrasonic dispersion, with an ultrasonic dispersion time of 30-60 minutes and an ultrasonic dispersion temperature of 50-60℃.

[0018] In practice, silicone molds of suitable size can be prepared using CO2 laser cutting technology.

[0019] In a preferred embodiment, when preparing a patterned shape memory adhesive material, the mold preparation process is as follows: A patterned silicone pad A is obtained by cutting a silicone pad with a CO2 laser to create the desired patterned groove; then, a silicone pad B of the same size as silicone pad A is placed below silicone pad A as the bottom surface, and the mold is assembled. In a preferred embodiment of the present invention, the mold is prepared using CO2 laser cutting technology, and its shape and thickness are easily controlled. A one-step preparation method by pouring a mixed solution into the mold yields an adhesive patch suitable for adhesion to various surfaces, such as rough and smooth surfaces.

[0020] In a preferred embodiment, the temperature of the heating stage is 50~60℃. Performing ultraviolet light initiation at this temperature ensures that the preparation process is carried out at an ambient temperature above the melting point of all raw materials, avoiding the influence of temperature on the degree of reaction, thereby obtaining an adhesive material with excellent performance.

[0021] In a preferred embodiment, the wavelength of the ultraviolet light used during ultraviolet light initiation is 365 nm.

[0022] In a preferred embodiment, the crosslinking polymerization reaction takes 15 to 25 minutes.

[0023] In a preferred embodiment, the heat treatment temperature is 60-70°C, and the heat treatment time is 2-3 hours. The cross-linked polymer containing oligomers is placed in an environment above its melting point for 2-3 hours to remove the oligomers and prevent residues from remaining on the skin surface during subsequent use.

[0024] The shape memory adhesive material provided by this invention can be used for adhesion to various materials, such as PET, metal, 3D printing resin, glass sheets, filter paper, and silicone, and exhibits strong adhesion. Therefore, this material can replace double-sided tape and self-adhesive silicone as an adhesive patch for reversible adhesion between many flexible devices and skin. Furthermore, due to its washable and shape memory properties, this adhesive patch is reusable.

[0025] The present invention also provides an application of a temperature-reversible and washable shape memory adhesive material, which is used as an adhesive patch in a rigid-soft bonded detachable microfluidic device.

[0026] Because the shape memory adhesive material provided by this invention has strong adhesion to different surfaces, it can replace double-sided tape as an adhesive patch for reversible adhesion between soft and hard bonding microfluidic devices and skin.

[0027] In application, a microfluidic chip capable of collecting and storing sweat is first drawn using 3D modeling software and then printed using a 3D printer. After cleaning, the resulting chip becomes the rigid part of the soft-hard bonded, detachable microfluidic device, which is entirely made of hydrophilic material. At temperatures above skin temperature, the soft adhesive patch and the rigid part bond tightly, with the soft part adhering firmly to the skin. Simultaneously, due to the inherent properties of the material, when the microfluidic device is on the skin, sweat, due to capillary action, is directionally transported from the adhesive patch to the rigid part through pre-drilled pores, facilitating sweat collection and storage for in vitro detection. After use, placing the device in an environment below skin temperature allows the adhesive patch to detach from the skin, with the areas adhering to the skin detaching preferentially over those adhering to the device. This maintains the integrity of the device, and both the soft and rigid parts can be disassembled.

[0028] Furthermore, due to the material's strong shape memory and washability, the prepared adhesive patch can be cleaned and dried above the material's melting point after disassembly, thus obtaining a clean and tidy adhesive patch that retains its original shape. Therefore, it can be reused multiple times. The shape memory property can protect the microfluidic channels reserved in the adhesive patch. Compared with other commonly used adhesive materials that cannot be reversibly adhered and can only be used once, this material shows a great advantage.

[0029] The main body of the microfluidic device is a rigid part printed by 3D modeling. Its shape and size are controlled by the system, the differences between devices are small, and the chip can be used multiple times.

[0030] The microfluidic device can perform directional transport and collection of sweat. The preparation process is simple, and the directional transport characteristics are determined by the material itself, without the need for any additional hydrophilic treatment.

[0031] The microfluidic device is detachable and can be used for in vitro sweat analysis and detection.

[0032] The adhesive patch has shape memory properties, which avoids the problem of mismatch with the microfluidic channel, and can be reused after disassembly.

[0033] The adhesive patch is washable, and can be easily cleaned with water or alcohol even after being stained, without affecting the adhesion of the material itself.

[0034] This invention relates to the application of a temperature-reversible and washable shape memory adhesive material, which is then used in a wearable flexible strain sensor. A superhydrophobic conductive layer is constructed on the surface of the adhesive material using an "adhesive + powder" method to fabricate the wearable flexible strain sensor. Because it better conforms to the skin, this sensor can be used to detect subtle physiological signals in the human body, providing accurate and real-time signals.

[0035] In a preferred embodiment, the fabrication process of the wearable flexible strain sensor is as follows: an Ecoflex solution is spin-coated onto the surface of a shape memory adhesive material to form an adhesive layer; multi-walled carbon nanotubes (CNTs) are composited into the adhesive layer to form a superhydrophobic conductive layer; finally, conductive electrodes are fabricated on the surface of the superhydrophobic conductive layer, and then wires are welded to the conductive electrodes.

[0036] In a further preferred embodiment, Ecoflex solution is uniformly spin-coated onto the surface of the shape memory adhesive material at a rotation speed of 1500 rpm to 2000 rpm for 20 to 40 seconds to form an adhesive layer.

[0037] Further optimization involves using a rod coating method to combine CNTs with the adhesive in the adhesive layer and then heat curing at 60-70°C for 2-3 hours to form a superhydrophobic conductive layer.

[0038] When applying shape memory adhesive materials to wearable flexible strain sensors, the process begins with preparing a silicone mold of suitable size using CO2 laser cutting technology. The adhesive material is then used as the substrate for the strain sensor. Next, a prepared Ecoflex solution is uniformly spin-coated onto the surface of the adhesive material at 1500-2000 rpm for 20-40 seconds to form an "adhesive" layer. Multi-walled carbon nanotubes (CNTs) are selected as the conductive medium, and a superhydrophobic conductive layer is prepared using an "adhesive-powder" method. Finally, conductive electrodes are constructed on top of the conductive layer, and wires are welded to obtain a flexible wearable strain sensor that can be used to monitor human physiological signals. Its bottom surface exhibits reversible adhesion and a perfect fit to the skin. This device can be used to monitor subtle physiological signals in the human body, providing accurate and real-time signals.

[0039] The sensor provided by this invention requires no additional adhesive layer and has temperature-reversible adhesion characteristics. The size of the sensor can be prepared by mold cutting as needed. The sensor adhesive layer serves as the substrate, resulting in more accurate signal transmission. The conductive layer is prepared by the "glue-powder" method, and the resulting composite material has both conductive and superhydrophobic properties. The conductive medium is CNTs. Due to the aspect ratio of the material itself, the composite conductive layer has linear response characteristics when used as a structureless strain sensor.

[0040] The beneficial effects of this invention are as follows:

[0041] 1. This invention prepares a temperature-reversible and washable shape memory adhesive material by initiating free radical polymerization with ultraviolet light of a specific wavelength. The material has a simple preparation process and excellent performance.

[0042] 2. The adhesive material of this invention can be used to adhere to a variety of surfaces, including rough and smooth surfaces.

[0043] 3. This invention provides a fabrication process for a microfluidic device that combines soft and hard components and is reversibly detachable, and the collected sweat can be used for in vitro detection.

[0044] 4. This invention provides a strain sensor that does not require an additional adhesive layer and is reversibly self-adhesive, which can better fit the skin and measure signals more instantly and accurately. Attached Figure Description

[0045] Figure 1 The diagram shows the reversible adhesion process of the adhesive material prepared in Example 1 to the skin (left figure) and the cyclic data curve of the adhesion strength test under the corresponding conditions (right figure): After the adhesive material is placed on the skin, the material transforms into an amorphous form, which can perfectly fit the skin, adapt to various deformations and will not detach. However, when the temperature decreases, the material crystallizes, the adhesion force is greatly reduced, and it is easy to detach. The adhesion strength test at different temperatures also shows the reversible adhesion characteristics of the material, and it still has high adhesion strength after multiple cycles of use.

[0046] Figure 2 The diagram shows the data analysis related to the principle of reversible adhesion of the adhesive material prepared in Example 1, including dynamic modulus test (left) and phase transition temperature test curve (right). The corresponding data also show that the adhesion characteristics of the prepared adhesive material at different temperatures are due to the different morphologies of the material before and after the transition temperature: semi-crystalline state and amorphous state. By controlling the crystallization temperature, the appropriate range of the mass ratio of SA to DA was determined.

[0047] Figure 3 The left figure shows the shape memory process of the adhesive material prepared in Example 1, and the material recovery rate data curve after multiple cycles (right figure): The adhesive material has good shape memory characteristics, and even after 100 cycles of stretching, the material still has high recovery.

[0048] Figure 4 The images shown are actual pictures of the adhesive material prepared in Example 1 after it has been contaminated with pollutants and can be washed. The left picture shows the material before washing and the right picture shows the material after washing. This shows that after the surface is contaminated with pollutants such as sweat and dust, it can be cleaned with water or alcohol without affecting the material's adhesive properties.

[0049] Figure 5 This is a diagram showing the effect of the adhesive patch prepared in Example 2 adhering to the surfaces of various materials.

[0050] Figure 6 This is a schematic diagram of the 3D-printed rigid microfluidic chip structure in Example 3, which includes a sweat inlet, a liquid inlet channel, and a sweat collection chamber.

[0051] Figure 7 The image shows the performance characterization of the superhydrophobic conductive layer prepared by the "glue + powder" method in Example 4, including conductivity (left image) and surface contact angle test (right image), both of which indicate the successful preparation of the superhydrophobic composite conductive layer. Detailed Implementation

[0052] The present invention will be described in detail through the specific embodiments described below, but it is obvious that the scope of protection of the present invention is not limited to these embodiments.

[0053] Example 1

[0054] This embodiment illustrates a method for preparing a temperature-reversible and washable shape memory adhesive material according to the present invention, such as... Figure 1 As shown, it includes the following steps:

[0055] 1) Weigh octadecyl acrylate (SA) and dodecyl acrylate (DA) in a mass ratio of 3:2 and place them in a beaker. Add crosslinking agent UDA at 20% of their total mass, and add photoinitiator at a ratio of 1% DMPA and 0.5% Ben by weight.

[0056] 2) Heat the ultrasonic machine to 50°C, place the beaker in it and ultrasonically disperse for 30 minutes to ensure the raw material components are fully mixed;

[0057] 3) Pour the well-dispersed mixture into the mold and place it on a 50°C hot plate to maintain a reaction environment above the melting point of the raw materials;

[0058] 4) Photoinitiate polymerization on it using a UV lamp with a specific wavelength of -365nm for 20 minutes, then place it at 60℃ for 2 hours to remove oligomers, and then place it in a refrigerator for refrigeration before demolding to obtain the desired adhesive material.

[0059] In addition, under the same conditions as above, adhesive materials with SA to DA mass ratios of 1:4, 1:1, 3:2, 9:2, and 5:0 were also prepared.

[0060] Figure 1This diagram illustrates the reversible adhesion process of the adhesive material prepared in Example 1 onto the skin, along with the cyclic data curves of the adhesion strength test under the corresponding conditions. The left diagram shows that after the adhesive material is placed on the skin, it transforms into an amorphous state, perfectly conforming to the skin, adapting to various deformations, and not detaching. However, when the temperature decreases, the material crystallizes, significantly reducing adhesion and making it prone to detachment. The right diagram, showing adhesion strength tests conducted at 36°C and 20°C, also demonstrates the reversible adhesion characteristics of the material, and it still maintains high adhesion strength after multiple cycles of use.

[0061] Figure 2 The diagram shows the data analysis related to the principle of reversible adhesion of the adhesive material prepared in Example 1, including dynamic modulus test (left) and phase transition temperature test curve (right). The corresponding data also show that the adhesion characteristics of the prepared adhesive material at different temperatures are due to the different morphologies of the material before and after the transition temperature: semi-crystalline state and amorphous state. By controlling the crystallization temperature, the appropriate range of the mass ratio of SA to DA was determined.

[0062] Figure 3 The left figure shows the shape memory process of the adhesive material prepared in Example 1, and the material recovery rate data curve after multiple cycles (right figure): As can be seen from the right figure, the material still has high recovery even after 100 cycles of stretching.

[0063] Figure 4 The images shown are actual pictures of the adhesive material prepared in Example 1 after it has been contaminated with pollutants and can be washed. The left picture shows the material before washing and the right picture shows the material after washing. This shows that after the surface is contaminated with pollutants such as sweat and dust, it can be cleaned with water or alcohol without affecting the material's adhesive properties.

[0064] Example 2

[0065] This embodiment illustrates the preparation process of the adhesive patch in this invention, which includes the following steps:

[0066] 1) Use Auto-CAD to draw the pattern according to the required shape and import it into the CO2 laser cutting machine. After removing the adhesive from the surface of the silicone pad, place it in the corresponding position for laser cutting to obtain the hollow silicone pad with the required pattern. After cleaning it, place a clean silicone pad of the same size underneath it to assemble the mold with the required pattern.

[0067] 2) Fix the silicone pad mold on the glass plate and place it on a 50°C hot table. Pour in the prepared mixed solution, use photo-initiated polymerization and post-processing to obtain the adhesive patch with the desired pattern.

[0068] Figure 5This is a diagram showing the effect of the adhesive patch prepared in Example 2 adhering to the surfaces of various materials.

[0069] Example 3

[0070] This embodiment illustrates the fabrication process of the adhesive material used in the present invention for a flexible-rigid bonding-detachable microfluidic chip, which includes the following steps:

[0071] 1) Use 3D modeling software such as SolidWorks to create a microfluidic chip model including channels and collection cavities. Slice the model using specialized software and import it into a 3D printer for printing (using a photocurable, washable resin). After printing, disassemble and clean the chip to obtain the desired rigid parts; for example... Figure 6 The schematic diagram of the rigid microfluidic chip structure shown includes a sweat inlet, a liquid inlet channel, and a sweat collection chamber.

[0072] 2) Pour the prepared mixed solution into the silicone pad mold with the desired pattern and then perform photoinitiated polymerization to obtain the adhesive patch;

[0073] 3) Assembling the adhesive patch with the rigid layer yields a rigid-soft bonded, detachable microfluidic device;

[0074] 4) The device can be attached to the skin to collect sweat. The chip is reversibly adhesive, and its soft and hard parts are removable. The collected sweat can be used for in vitro detection.

[0075] Example 4

[0076] This embodiment illustrates the fabrication method of the wearable strain sensor in this invention:

[0077] 1) First, a silicone pad mold with dimensions of 30×5×0.5mm is prepared using a CO2 laser cutting machine;

[0078] 2) Prepare a mixed solution of the adhesive material and an Ecoflex solution with a mass ratio of A:B components of 1:1;

[0079] 3) A substrate with reversible adhesion properties and dimensions of 30×5×0.5mm was prepared using a mold;

[0080] 4) Use a spin coater to spin coat the Ecoflex solution onto the substrate at a speed of 2000 rpm for 30 seconds to prepare the "glue" layer;

[0081] 5) The CNTs were combined with "adhesive" by rod coating and then heat-cured at 60°C for 2 hours to obtain a superhydrophobic and conductive composite layer;

[0082] 6) Electrodes were prepared on the surface of the superhydrophobic conductive layer using conductive silicone and copper foil, and wires were connected by welding after thermal curing at 80°C for 4 hours.

[0083] 7) To prevent short circuits or other malfunctions of the electrodes due to water, the electrode part is treated with superhydrophobic potting compound and then heat-cured for 2 hours to obtain a wearable strain sensor that integrates reversible adhesion and superhydrophobicity.

[0084] Figure 7 The image shows the performance characterization of the superhydrophobic conductive layer prepared by the "glue + powder" method in Example 4, including conductivity (left image) and surface contact angle test (right image), both of which indicate the successful preparation of the superhydrophobic composite conductive layer.

[0085] The sensor produced can adhere to the skin itself without the need for an additional adhesive layer, resulting in higher accuracy and timeliness of the measured data, making it easier to use for real-time monitoring of human movement.

Claims

1. A method for preparing a temperature-reversible and washable shape memory adhesive material, characterized in that: Octadecyl acrylate, dodecyl acrylate, polyurethane diacrylate, DMPA, and Ben are mixed to obtain a mixed solution. The mixed solution is poured into a mold and placed on a hot plate. A cross-linking polymerization reaction is initiated by ultraviolet light to obtain a cross-linked polymer containing oligomers. The cross-linked polymer containing oligomers is heat-treated to remove the oligomers. After refrigeration, it is demolded to obtain the adhesive material. The heat treatment temperature is 60~70℃, and the heat treatment time is 2~3h; The shape memory adhesive material is a crosslinked polymer of octadecyl acrylate, dodecyl acrylate and polyurethane diacrylate, wherein the mass fraction of polyurethane diacrylate in the shape memory adhesive material is 15-25%, and the mass ratio of octadecyl acrylate to dodecyl acrylate is 1-1.

75.

2. The method for preparing a temperature-reversible and washable shape memory adhesive material according to claim 1, characterized in that: The mass ratio of octadecyl acrylate to dodecyl acrylate is 1~1.75; The DMPA has a mass fraction of 0.5-1% in the mixed solution, and the Ben has a mass fraction of 0.2-0.5% in the mixed solution. The mixing method is ultrasonic dispersion, the ultrasonic dispersion time is 30~60 min, and the ultrasonic dispersion temperature is 50~60℃.

3. The method for preparing a temperature-reversible and washable shape memory adhesive material according to claim 1, characterized in that: When preparing a patterned shape memory adhesive material, the mold preparation process is as follows: a patterned silicone pad A is obtained by cutting a silicone pad with a CO2 laser to create the required patterned groove, and then a silicone pad B of the same size as the silicone pad A is placed below the silicone pad A as the bottom surface and assembled into a mold.

4. The method for preparing a temperature-reversible and washable shape memory adhesive material according to claim 1, characterized in that: The temperature of the heating platform is 50~60℃; When the ultraviolet light is used for initiation, the wavelength of the ultraviolet light is 365nm; The crosslinking polymerization reaction takes 15-25 minutes.

5. The method for preparing a temperature-reversible and washable shape memory adhesive material according to claim 1, characterized in that: The phase transition temperature of the shape memory adhesive material is 28-33℃.

6. The application of a temperature-reversible and washable shape memory adhesive material prepared by the preparation method according to any one of claims 1-5, characterized in that: The shape memory adhesive material is used as an adhesive patch in a rigid-soft bonded detachable microfluidic device.

7. The application of a temperature-reversible and washable shape memory adhesive material prepared by the preparation method according to any one of claims 1-5, characterized in that: The shape memory adhesive material is applied to wearable flexible strain sensors.

8. The application of the temperature-reversible and washable shape memory adhesive material according to claim 7, characterized in that: The fabrication process of the wearable flexible strain sensor is as follows: an Ecoflex solution is spin-coated onto the surface of a shape memory adhesive material to form an adhesive layer; multi-walled carbon nanotubes are composited into the adhesive layer to form a superhydrophobic conductive layer; finally, conductive electrodes are fabricated on the surface of the superhydrophobic conductive layer, and then wires are welded to the conductive electrodes. Ecoflex solution is uniformly spin-coated onto the surface of the shape memory adhesive material at a speed of 1500 rpm to 2000 rpm for 20 to 40 seconds to form an adhesive layer; The CNTs were bonded to the adhesive in the adhesive layer using a rod coating method and then heat-cured at 60-70℃ for 2-3 hours to form a superhydrophobic conductive layer.

Images