Bidirectional driver based on nematic phase liquid crystal elastomer-silica gel as well as preparation method and application of bidirectional driver

Abstract

The invention relates to the technical field of intelligent material drivers, in particular to a bidirectional driver based on nematic phase liquid crystal elastomer-silica gel and a preparation method and application of the bidirectional driver. The preparation method comprises the following steps: S1, selecting a nematic phase liquid crystal elastomer capable of shrinking in the main axis direction, and processing and preparing the nematic phase liquid crystal elastomer into a sheet structure with a smooth surface; s2, the temperature of a heating table is increased to a preset preparation temperature, and the nematic phase liquid crystal elastomer is placed on the heating table; s3, when the nematic phase liquid crystal elastomer is heated and does not deform any more, one side of the nematic phase liquid crystal elastomer is rapidly coated with the prepared silica gel; s4, placing the nematic phase liquid crystal elastomer on a heating table, and maintaining the nematic phase liquid crystal elastomer at the preparation temperature; and S5, after the silica gel is dried, naturally cooling. The nematic phase liquid crystal elastomer driver can achieve the bidirectional bending characteristic, flexible movement of the driver is achieved, the manufacturing efficiency is high, the cost is low, and the application range of the nematic phase liquid crystal elastomer driver in the fields of intelligent materials and robots is widened.

Description

Technical Field

[0001] The present invention relates to the technical field of intelligent material actuators, and particularly to a bidirectional actuator based on nematic liquid crystal elastomer-silicone and its preparation method and application. Background Art

[0002] Liquid crystal elastomers are a type of soft intelligent material. After a liquid crystal polymer is moderately crosslinked, it is a special material with the dual characteristics of liquid crystals and elastomers. Nematic liquid crystal elastomers can produce significant shape changes in response to external stimuli such as temperature, light, and electric fields. They have high reversibility and flexibility, and can also exhibit excellent response speed and low energy consumption characteristics, making them excellent materials for preparing actuators. Nematic liquid crystal elastomers have now become a research hotspot in the field of intelligent material actuators. However, the preparation of nematic liquid crystal elastomer actuators is relatively complex. It requires cumbersome chemical synthesis and polymerization reactions to generate nematic liquid crystal elastomer materials, and precise curing is needed to ensure the accuracy of the contraction direction. In addition, the prepared nematic liquid crystal elastomer actuators generally can only achieve contraction or one-way bending, lacking diversity in responding to external stimuli, resulting in their driving ability being mainly concentrated on linear motion or one-way bending, which greatly limits the flexibility and functionality of the actuators in various practical applications. For example, in the fields of soft robots, wearable devices, and intelligent material systems, a single deformation mode cannot meet the requirements of complex movements. Actuators are often required to be able to respond to external stimuli in multiple directions to achieve complex movements or shape changes. Summary of the Invention

[0003] The purpose of the present invention is, in view of the above deficiencies of the prior art, to provide a bidirectional actuator based on nematic liquid crystal elastomer-silicone and its preparation method and application, enabling the nematic liquid crystal elastomer actuator to achieve bidirectional bending characteristics, realizing the flexible movement of the actuator, while improving the production efficiency, saving production costs, broadening the application scope of the nematic liquid crystal elastomer actuator in the fields of intelligent materials and robots, and promoting the development of intelligent material actuator technology and the field of soft robots.

[0004] The first object of the present invention is to provide a preparation method of a bidirectional actuator based on nematic liquid crystal elastomer-silicone, comprising the following steps:

[0005] S1: Select a nematic liquid crystal elastomer that can contract along the principal axis direction, and process it into a smooth sheet structure.

[0006] S2: Raise the temperature of the heating table to a preset preparation temperature, and place the prepared sheet-like nematic liquid crystal elastomer on the heating table.

[0007] S3: When the nematic liquid crystal elastomer is heated to a certain contraction state and no longer deforms, quickly apply the prepared silicone rubber on one side of the nematic liquid crystal elastomer;

[0008] S4: Place the nematic liquid crystal elastomer on a heating table and maintain its temperature at the preparation temperature;

[0009] S5: After the silicone rubber dries, remove the actuator from the heating table and cool it in a room temperature environment.

[0010] Further, the preparation temperature is 50 - 60 °C.

[0011] Further, mix agent A and agent B of the silicone rubber in a mass ratio of 1:1, and continuously stir for two minutes until agents A and B are fully and evenly mixed, while avoiding the generation of bubbles.

[0012] The second object of the present invention is to provide a bidirectional actuator based on a nematic liquid crystal elastomer - silicone rubber prepared by the preparation method as described above.

[0013] The third object of the present invention is to provide an application of a bidirectional actuator based on a nematic liquid crystal elastomer - silicone rubber as described above, and the actuator can achieve bidirectional bending and dynamically adjust the bending direction and angle through temperature control.

[0014] Further, the actuator bends towards the silicone rubber side in the initial state at room temperature, and the bending direction and the magnitude of the bending angle are switched through temperature adjustment;

[0015] In the actuator, the nematic liquid crystal elastomer shrinks along the main axis direction when heated, while the silicone rubber remains unchanged. As the temperature rises, the degree of bending of the actuator towards the silicone rubber side gradually decreases; when the temperature of the actuator reaches the preparation temperature, the actuator is in a horizontal state; as the temperature continues to rise, the actuator bends towards the nematic liquid crystal elastomer side, and as the temperature rises, the degree of bending of the actuator towards the nematic liquid crystal elastomer side gradually increases;

[0016] In the actuator, the nematic liquid crystal elastomer elongates along the main axis direction when cooled, while the silicone rubber remains unchanged. As the temperature drops, the degree of bending of the actuator towards the nematic liquid crystal elastomer side gradually decreases. When the temperature of the actuator reaches the preparation temperature, the actuator is in a horizontal state; as it continues to cool, the actuator bends towards the silicone rubber side, and as the temperature drops, the degree of bending of the actuator towards the silicone rubber side gradually increases.

[0017] Further, it is applied to intelligent robots to imitate the motion patterns of biological muscles and improve the flexibility and adaptability of the robots.

[0018] Further, it is applied to flexible electronic devices to enhance the flexibility and comfort of the devices.

[0019] A bidirectional driver based on nematic liquid crystal elastomer-silicone designed by the present invention, compared with the limitation of traditional nematic liquid crystal elastomer drivers that can only achieve contraction or unidirectional deformation, this driver has the characteristic of bidirectional bending, greatly expanding the application scope of nematic liquid crystal elastomer drivers. Especially in the fields of intelligent robots, intelligent material drivers, and flexible electronic devices, its application potential has been significantly improved. In the field of intelligent robots, this driver can be used to imitate the motion mode of biological muscles, improving the flexibility and adaptability of robots; in flexible electronic devices, the bidirectional bending ability provided by this driver can enhance the flexibility and comfort of the devices.

[0020] The present invention has relatively loose requirements for the nematic liquid crystal elastomers used, and is applicable to almost all types of sheet-like nematic liquid crystal elastomers, increasing the wide material applicability. This characteristic not only facilitates production and application, but also effectively reduces the complexity in the process of material procurement and storage. During the manufacturing and application processes, manufacturers no longer need to be restricted to specific types of nematic liquid crystal elastomers, thus reducing the threshold of research and development and production, and contributing to the popularization and wide application of material technology.

[0021] The driver proposed by the present invention combines nematic liquid crystal elastomers and silicone, integrating the excellent thermal response characteristics of nematic liquid crystal elastomers and the high durability of silicone, enabling it to have controllable shape changes and good mechanical properties, showing wide applicability and potential in many application fields.

[0022] The entire preparation process of the present invention is carried out in an environment above room temperature, without relying on long-term natural air drying, significantly shortening the air drying time of silicone. Due to the accelerated curing rate of silicone caused by continuous heating, this method can adapt to different environmental temperature conditions, is not affected by room temperature, making the production process more flexible and efficient, and improving the preparation efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 Shows the state of a bidirectional driver based on nematic liquid crystal elastomer-silicone of the present invention at the preparation temperature;

[0024] Figure 2 Schematic diagram of the working state of a bidirectional driver based on nematic liquid crystal elastomer-silicone in an example of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0025] The following are specific embodiments of the present invention in combination with the drawings, further describing the technical solutions of the present invention, but the present invention is not limited to these embodiments.

[0026] Example 1

[0027] An embodiment of the present invention provides a preparation method of a bidirectional driver based on a nematic liquid crystal elastomer-silicone, including:

[0028] S1: Select a nematic liquid crystal elastomer that can shrink upon heating along the principal axis direction, and process it into a sheet structure with a smooth surface.

[0029] S2: Raise the temperature of the heating table to 50-60 degrees Celsius, and place the prepared sheet-like nematic liquid crystal elastomer on the heating table. The nematic liquid crystal elastomer shrinks along the principal axis direction due to heating.

[0030] S3: When the nematic liquid crystal elastomer reaches a certain contraction state upon heating and no longer deforms, quickly apply the prepared silicone on one side of the nematic liquid crystal elastomer.

[0031] S4: After the silicone application is completed, place the nematic liquid crystal elastomer on the heating table and continue heating, and maintain its temperature at the preparation temperature;

[0032] S5: After the silicone dries, remove the driver from the heating table and place it in a room temperature environment to cool.

[0033] In S1, the requirements for the type of nematic liquid crystal elastomer are relatively loose. Any nematic liquid crystal elastomer that can achieve uniform contraction along the principal axis direction can be applicable and can be obtained through existing technologies. A smooth surface is crucial for applying silicone. A smooth surface not only helps the uniform application of silicone, but also significantly improves the adhesion between the silicone and the nematic liquid crystal elastomer, preventing the appearance of bubbles or other defects during the process. This fine surface treatment not only improves the effective coverage of the silicone, but also enhances the mechanical properties and functional stability of the driver.

[0034] At room temperature, the liquid crystal molecules inside the nematic liquid crystal elastomer are arranged orderly along the principal axis direction as a whole. Under thermal stimulation, the liquid crystal molecules undergo a phase change: when heated, as the temperature rises, the liquid crystal molecules gradually change from an ordered state to a disordered state, which macroscopically manifests as the nematic liquid crystal elastomer shrinking along the principal axis direction; when cooled, the liquid crystal molecules gradually change from a disordered state to an ordered state arranged along the principal axis, which macroscopically manifests as the nematic liquid crystal elastomer elongating along the principal axis direction. Generally, when the surface temperature of the nematic liquid crystal elastomer rises to 90 degrees Celsius, its deformation amount will reach 80%-90% of the maximum deformation. Therefore, in S2, selecting the preparation temperature at 50-60 degrees Celsius can make the nematic liquid crystal elastomer in a moderate deformation state.

[0035] In S3, when the surface temperature of the nematic liquid crystal elastomer reaches the preset preparation temperature and the deformation becomes stable, a silicone rubber with a certain Shore hardness should be quickly applied to one side according to the preparation requirements to meet the specific needs of the preparation. During the application process, ensure that the silicone rubber is evenly applied and avoid the generation of air bubbles to ensure the stable performance of the prepared actuator. The even application of silicone rubber can not only improve adhesion but also enhance the structural integrity and functional stability of the actuator.

[0036] In this embodiment, the silicone rubber is configured by the following method: Mix the component A and component B of the purchased silicone rubber in a mass ratio of 1:1, and continuously stir for two minutes until the A and B adhesives are fully and evenly mixed, while avoiding the generation of air bubbles.

[0037] In S4, the main purpose of continuously heating the nematic liquid crystal elastomer is to accelerate the drying and curing speed of the silicone rubber, so as to ensure that the silicone rubber can form a stable adhesive force after curing and form a good bonding interface. In addition, maintaining a high-temperature state helps to reduce and prevent the interference of moisture in the air on the curing of the silicone rubber and ensure the stability of the actuator during the processing. To achieve the best effect, the continuous heating time should be long enough until the silicone rubber is completely dry and has ideal mechanical properties.

[0038] In S5, remove the actuator from the heating table, and the nematic liquid crystal elastomer starts to cool naturally. As the temperature gradually decreases, the nematic liquid crystal elastomer will gradually elongate along the main axis direction, while the silicone rubber will remain in its original state due to its curing characteristics. There are significant physical differences between the nematic liquid crystal elastomer and the silicone rubber, and this difference leads to uneven stress inside the actuator, and the actuator will bend towards the silicone rubber side, forming the initial bending state of the nematic liquid crystal elastomer-silicone rubber bidirectional actuator at room temperature.

[0039] Figure 1 This is the state of the bidirectional actuator based on nematic liquid crystal elastomer-silicone rubber of the present invention at the preparation temperature. In Figure 1 The bottom of the actuator is composed of a flat sheet of nematic liquid crystal elastomer, and the top is covered with a silicone rubber layer after application and curing treatment. The up and down order of the two can be reversed. Through this composite structure, the actuator can exhibit excellent bending ability during application, enabling it to meet the performance standards required for various dynamic load requirements and actual application scenarios.

[0040] Example 2

[0041] Figure 2This is a schematic diagram of the working state of a bidirectional driver based on a nematic liquid crystal elastomer-silicone gel according to an example of the present invention. At room temperature, the driver will bend toward the side of the silicone gel, and at this time it is in the initial state of the driver. The driver is heated uniformly, and as the temperature rises, the nematic liquid crystal elastomer will shrink along the main axis direction, while the silicone gel will remain in its original state due to its curing characteristics, so the degree of bending of the driver as a whole toward the silicone gel side slowly decreases, and tends to be flat in the horizontal direction. When the surface temperature of the nematic liquid crystal elastomer reaches the temperature required for preparing the driver, the driver will be in a horizontal state. As the heating continues, the surface temperature of the nematic liquid crystal elastomer exceeds the temperature for preparing the driver, and the nematic liquid crystal elastomer continues to shrink, and its length is less than the length at the preparation temperature. During the whole process, the silicone gel remains in its original state, so the driver will bend toward the side of the nematic liquid crystal elastomer, and as the temperature rises, the degree of bending of the driver toward the side of the nematic liquid crystal elastomer slowly increases.

[0042] During cooling, as the surface temperature of the nematic liquid crystal elastomer gradually decreases, the nematic liquid crystal elastomer will stretch along the main axis. In the initial stage of cooling, the driver still bends toward the nematic liquid crystal elastomer. As the temperature decreases, the degree to which the driver bends toward the nematic liquid crystal elastomer gradually decreases. When the surface temperature of the nematic liquid crystal elastomer drops to the temperature required for preparing the driver, the driver is in a horizontal state. As cooling continues, the surface temperature of the nematic liquid crystal elastomer is lower than the temperature for preparing the driver, and the nematic liquid crystal elastomer continues to stretch, and its length is greater than the length at the preparation temperature. Therefore, the driver will bend toward the silicone side, and as the temperature decreases, the degree to which the driver bends toward the silicone side gradually increases.

[0043] By precisely controlling the temperature, the bending direction and bending angle of the actuator in the present invention can be accurately adjusted. Therefore, temperature as a control parameter of the actuator can enable it to achieve flexible and accurate motion adjustment in different application scenarios, which provides new possibilities for realizing various intelligent control systems, makes it possible to execute complex motion patterns, and further promotes the research of bio-inspired robots and bionics.

[0044] For matters not mentioned above, the prior art applies.

[0045] Although some specific embodiments of the present invention have been described in detail by way of examples, those skilled in the art should understand that the above examples are for illustrative purposes only and not for limiting the scope of the present invention. Those skilled in the technical field to which the present invention pertains can make various modifications or supplements to the described specific embodiments or use similar ways for substitution, but will not deviate from the direction of the present invention or exceed the scope defined by the appended claims. Those skilled in the art should understand that any modifications, equivalent substitutions, improvements, etc. made to the above embodiments based on the technical essence of the present invention should all be included within the protection scope of the present invention.

Claims

1. A method for preparing a bidirectional actuator based on nematic liquid crystal elastomer-silicone, characterized in that: The steps include: S1: Select a nematic liquid crystal elastomer that can shrink along the main axis and process it into a sheet structure with a smooth surface; S2: raising the temperature of the heating platform to a preset preparation temperature, and placing the prepared sheet-like nematic liquid crystal elastomer on the heating platform; S3: When the nematic liquid crystal elastomer reaches a certain shrinkage state after being heated and no longer deforms, quickly apply the prepared silicone on one side of the nematic liquid crystal elastomer; S4: placing the nematic liquid crystal elastomer on a heating table and maintaining the temperature thereof at a preparation temperature; S5: After the silicone is dry, remove the actuator from the heating table and allow it to cool at room temperature.

2. The preparation method according to claim 1, characterized in that: The preparation temperature is 50-60°C.

3. The preparation method according to claim 1, characterized in that: The silica gel is prepared in the following way: Mix the A and B agents of silica gel in a mass ratio of 1:1, and continue stirring for two minutes until the A and B glues are fully mixed while avoiding the generation of bubbles.

4. A bidirectional actuator based on nematic liquid crystal elastomer-silicone prepared by the preparation method as described in any one of claims 1 to 3.

5. An application of the bidirectional actuator based on nematic liquid crystal elastomer-silicone as claimed in claim 4, characterized in that: The actuator can realize bidirectional bending and dynamically adjust the bending direction and angle through temperature control.

6. An application of the bidirectional actuator based on nematic liquid crystal elastomer-silicone as claimed in claim 5, characterized in that: The actuator initially bends toward the silicone side at room temperature, and the bending direction and the bending angle are switched by temperature adjustment. The nematic liquid crystal elastomer in the driver shrinks along the main axis when heated, while the silicone remains unchanged, and the degree of bending of the driver toward the silicone gradually decreases as the temperature rises; when the temperature of the driver reaches the preparation temperature, the driver is in a horizontal state; as the temperature continues to rise, the driver bends toward the nematic liquid crystal elastomer, and as the temperature rises, the degree of bending of the driver toward the nematic liquid crystal elastomer gradually increases; The nematic liquid crystal elastomer in the driver stretches along the main axis when cooled, while the silicone remains unchanged, and the degree of bending of the driver toward the nematic liquid crystal elastomer gradually decreases as the temperature drops. When the driver temperature reaches the preparation temperature, the driver is in a horizontal state; as the cooling continues, the driver bends toward the silicone, and as the temperature drops, the degree of bending of the driver toward the silicone gradually increases.

7. An application of the bidirectional actuator based on nematic liquid crystal elastomer-silicone as claimed in claim 5, characterized in that: Applied to intelligent robots to imitate the movement patterns of biological muscles and improve the flexibility and adaptability of robots.

8. An application of the bidirectional actuator based on nematic liquid crystal elastomer-silicone as claimed in claim 5, characterized in that: Applied to flexible electronic devices to enhance the flexibility and comfort of the devices.

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