A multi-stimuli responsive actuated film and a method of making the same

Abstract

The present application relates to the technical field of flexible driving film, and particularly relates to a multi-stimulus response driving film and a preparation method thereof. The flexible driving film is formed by combining graphene paper and MWCNTs / PDMS prepolymer through a semi-curing process, and the specific preparation method comprises the following steps: (1) taking single-sided surface roughening treated A4 paper as a substrate, dropping graphene dispersion liquid, and forming graphene paper after drying; (2) uniformly mixing multi-walled carbon nanotubes (MWCNTs) and polydimethylsiloxane (PDMS) through ultrasonic dispersion, and forming MWCNTs / PDMS prepolymer through solvent evaporation; (3) realizing the interface combination of graphene paper and MWCNTs / PDMS prepolymer through a semi-curing process, and obtaining a PDMS flexible driving film. The PDMS flexible driving film prepared by the present application can produce controllable bending deformation under light, temperature and humidity stimulation, and has the characteristics of simple preparation method, large bending driving amplitude and high interface bonding strength. The present application is suitable for the fields of flexible robots, intelligent sensors and the like.

Description

Technical Field

[0001] This invention relates to the field of flexible actuator technology, and in particular to a multi-stimulus responsive driving thin film and its preparation method. Background Technology

[0002] Traditional rigid actuators play a vital role in automated production, but their inherent drawbacks, such as bulky structure, insufficient environmental adaptability, and high risks associated with human-machine interaction, limit their application in complex scenarios, especially in fields requiring direct contact with the human body, such as medical rehabilitation and wearable devices, where they can easily pose safety hazards. In contrast, flexible actuator films with low elastic modulus and high deformation capacity have significant advantages in flexible interaction.

[0003] Flexible actuation films can exhibit significant physical changes in shape under external stimuli such as light, heat, electric fields, and magnetic fields, including dynamic deformation behaviors such as bending, stretching, and torsion. Compared to traditional rigid actuators, the core advantages of flexible actuation films lie in their flexibility, adaptability, and safety. Their deformation process is highly reversible; when the external stimulus is removed, the material can autonomously return to its initial shape, and this response mechanism can be repeatedly triggered when external conditions change periodically.

[0004] Significant progress has been made in the research of flexible actuation films, but many problems still need to be solved, including complex fabrication processes, high material costs, and the limited availability of actuation stimuli. Therefore, developing intelligent flexible actuation films with simple fabrication processes, low manufacturing costs, excellent actuation performance, and support for multi-stimuli responses is of great research value and application significance. Summary of the Invention

[0005] The technical problem to be solved by this invention is how to address the issues of existing flexible driven thin films having a single driving stimulus source, high material costs, and complex preparation processes.

[0006] To achieve the above-mentioned objective, the present invention provides a method for preparing a multi-stimulus-responsive driven thin film, comprising the following steps:

[0007] (1) Preparation of graphene paper: Use low-tack masking tape to evenly adhere along the direction parallel to the A4 paper fibers and perform a uniform peeling operation to form a single-sided high-roughness surface of the A4 paper; drop graphene aqueous dispersion onto the rough paper surface, spread evenly with a scraper, place on a heating table to dry the moisture and flatten to obtain a flat graphene paper.

[0008] (2) Preparation of MWCNTs / PDMS prepolymer: MWCNTs and PDMS are dissolved in organic solvents and mixed. The mixture is ultrasonically treated to completely disperse MWCNTs in PDMS. The solvent is heated to evaporate completely. A curing agent is added to the mixed solution in proportion and stirred evenly to obtain MWCNTs / PDMS prepolymer.

[0009] (3) Preparation of PDMS flexible driving film: The MWCNTs / PDMS prepolymer prepared in step (2) is spread evenly on the surface of a planar mold, coated into a film using a coater, and transferred to a constant temperature oven for heating to semi-cur. Then, the graphene paper prepared in step (1) is laid flat on the semi-cured MWCNTs / PDMS prepolymer, a weight is applied to make it adhere tightly together, and heating is continued to make it completely cured to obtain PDMS flexible driving film.

[0010] Preferably, in step (1), the concentration of the graphene aqueous dispersion is 2 mg / ml, and the drop volume is 2-8 mg / (25cm³). 2 ).

[0011] Beneficial effects: Drop-coating of graphene aqueous dispersion enhances the thermodynamic properties of flexible actuation films, improves actuation performance, and reduces actuation response time.

[0012] Preferably, in step (1), the drying temperature of the heating table is set to 60°C and the drying time is 4 hours.

[0013] Preferably, the organic solvent in step (2) includes at least one of toluene, n-hexane and propanol; MWCNTs include at least one of surface-hydroxylated multi-walled carbon nanotubes, surface-aminated multi-walled carbon nanotubes and pure carbon nanotubes.

[0014] Beneficial effects: MWCNTs have high surface energy and are prone to aggregation. Using a solution blending method to mix MWCNTs with PDMS in an organic solvent, and using surface-modified MWCNTs and ultrasonic dispersion helps to disperse MWCNTs.

[0015] Preferably, in step (2), the ultrasonic power is 300W and the ultrasonic time is 1h; the mass ratio of curing agent to PDMS is 1:10.

[0016] Preferably, the thickness of the film formed by scraping in step (3) is 100 to 1000 μm.

[0017] Beneficial effects: The thickness of the prepared PDMS flexible actuation film is selectable, and the bending actuation requirements in different scenarios can be met by controlling the thickness.

[0018] Preferably, the parameters of the semi-curing constant temperature oven in step (3) are 80°C for 5 minutes and the parameters of the fully curing constant temperature oven are 80°C for 360 minutes.

[0019] The advantages of this invention are:

[0020] 1. When the PDMS flexible driving film proposed in this invention is stimulated by light and temperature, the PDMS expands due to heat, and the driving film bends towards the A4 paper side; when stimulated by humidity, the A4 paper absorbs moisture and expands, and the driving film bends towards the PDMS side, thus satisfying the multi-stimulus response requirements of the flexible driving film.

[0021] 2. The PDMS used in this invention differs significantly from A4 paper in terms of thermal expansion coefficient and moisture absorption properties. Both can undergo significant bending actuation when subjected to light, temperature, and humidity stimuli, meeting the requirement for excellent actuation performance of flexible actuation films.

[0022] 3. The A4 paper and PDMS used in this invention have low cost, and the semi-cured direct lamination process is simple, meeting the requirements of simple flexible drive film preparation process and low manufacturing cost. Attached Figure Description

[0023] The disclosure of this invention will become more readily understood with reference to the accompanying drawings.

[0024] Figure 1 This is a schematic diagram illustrating the fabrication of the PDMS flexible driving film in Example 1 of the present invention;

[0025] Figure 2 This is a SEM image of the layering and interface bonding of the PDMS flexible driving film in Embodiment 1 of the present invention;

[0026] Figure 3 This is a test of the bending drive performance of the PDMS flexible driving film in Example 1 of the present invention under 4000 lux light stimulation;

[0027] Figure 4 This is a test of the bending drive performance of the PDMS flexible driving film in Example 1 of the present invention under temperature stimulation of 80°C;

[0028] Figure 5 This is a test of the bending drive performance of the PDMS flexible driving film in Example 1 of the present invention when the relative humidity increases from 45%RH to 85%RH. Detailed Implementation

[0029] The technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings, but the content of the present invention is not limited to the following embodiments.

[0030] Example 1

[0031] A multi-stimulus responsive driven thin film and its preparation method are characterized by the following preparation steps:

[0032] (1) Preparation of graphene paper: Low-tack masking tape was uniformly applied along the fiber direction of A4 paper and peeled off at a constant speed to form a single-sided high-roughness surface on the A4 paper; the graphene aqueous dispersion was then added at a concentration of 6 mg / 25 cm⁻¹. 2 The loading amount is dripped onto the rough paper surface, spread evenly with a scraper, placed on a heating table and heated at 60°C for 2 hours to fully dry the moisture and flatten it to obtain a smooth graphene paper.

[0033] (2) Preparation of MWCNTs / PDMS prepolymer: 0.1g MWCNTs and 10g PDMS were dissolved in toluene and magnetically stirred for 10 minutes to mix them. The mixture was then ultrasonically treated at 300W for 1 hour to completely disperse the MWCNTs in the PDMS. The mixed solution was placed in an 80℃ constant temperature water bath stirring device and continuously treated at 300r / min for 4 hours. The curing agent was added to the mixed solution at a mass ratio of PDMS to curing agent of 10:1 and stirred evenly. The mixture was placed in a vacuum environment for 30 minutes to remove air bubbles and obtain the MWCNTs / PDMS prepolymer.

[0034] (3) Preparation of PDMS flexible driving film: The MWCNTs / PDMS prepolymer prepared in step (2) is spread evenly on the surface of a planar mold, and a 200μm coater is used to coat it into a film. The film is then transferred to an 80℃ constant temperature oven and heated for 6 minutes to make it semi-cured. Then, the graphene paper prepared in step (1) is laid flat on the semi-cured MWCNTs / PDMS prepolymer, and a 200g weight is applied to make it adhere tightly together. The film is then heated at 80℃ for 4 hours to make it completely cured, thus obtaining the PDMS flexible driving film.

[0035] Figure 1 The diagram shown is a schematic diagram of the fabrication of the PDMS flexible driving film in this embodiment.

[0036] Figure 2 The image shown is a SEM image of the layering and interface bonding of the PDMS flexible driving film in this embodiment. The upper graphene paper and the lower PDMS are composited through a semi-curing process. The graphene paper fibers are deeply embedded in the PDMS polymer matrix, indicating that the two materials effectively achieve high-strength interface bonding.

[0037] The PDMS flexible actuation film prepared in this embodiment was subjected to light, temperature and humidity response tests to verify its actuation performance.

[0038] Figure 3The bending actuation performance of the PDMS flexible actuation film prepared in this embodiment was tested under 4000 lux light stimulation. Under 4000 lux light stimulation, the graphene paper of the PDMS flexible actuator prepared in this embodiment rapidly absorbed light energy and converted it into heat energy, resulting in an increase in the overall temperature of the actuator. The PDMS layer has a higher coefficient of thermal expansion, and its volume expansion is much greater than that of the graphene paper layer, thus generating a stress difference. As a result, the actuator bends towards the graphene paper side, with a maximum bending actuation angle of 230° and a bending actuation time of 35s.

[0039] Figure 4 The bending actuation performance of the PDMS flexible actuation film of the vegetation in this embodiment was tested under temperature stimulation of 80°C. The PDMS flexible actuator prepared in this embodiment achieved a maximum bending actuation angle of 268° under temperature stimulation of 80°C, and the bending actuation time was 50s.

[0040] Figure 5 The bending drive performance of the PDMS flexible driven film prepared in this embodiment was tested under relative humidity increasing from 45%RH to 85%RH. When the ambient relative humidity increased from 45%RH to 85%RH, the graphene paper fiber layer underwent significant volume expansion due to the adsorption of water molecules, while the PDMS layer showed almost no deformation due to its hydrophobicity. The difference in humidity-driven strain between the two layers drove the sample to bend towards the PDMS side, and the maximum bending drive angle reached 83° at an ambient relative humidity of 85%RH.

[0041] In summary, when the PDMS flexible driving film prepared in this embodiment is stimulated by light and temperature, the PDMS expands due to heat, and the driving film bends towards the A4 paper side; when stimulated by humidity, the A4 paper absorbs moisture and expands, and the driving film bends towards the PDMS side, thus meeting the requirements of multi-stimulus response of flexible driving films, and both can achieve large bending drive, thus meeting the requirement of excellent driving performance of flexible driving films.

[0042] Example 2

[0043] A multi-stimulus responsive driven thin film and its preparation method are characterized by the following preparation steps:

[0044] (1) Preparation of graphene paper: Low-tack masking tape was uniformly applied along the fiber direction of A4 paper and peeled off at a constant speed to form a single-sided high-roughness surface on the A4 paper; the graphene aqueous dispersion was added at 2 mg / 25 cm⁻¹ 2 The loading amount is dripped onto the rough paper surface, spread evenly with a scraper, placed on a heating table and heated at 60°C for 2 hours to fully dry the moisture and flatten it to obtain a smooth graphene paper.

[0045] (2) Preparation of MWCNTs / PDMS prepolymer: 0.2g MWCNTs and 10g PDMS were dissolved in toluene and magnetically stirred for 10 minutes to mix them. The mixture was ultrasonically treated at 300W for 1 hour to completely disperse MWCNTs in PDMS. The mixed solution was placed in an 80℃ constant temperature water bath stirring device and continuously treated at 300r / min for 4 hours. The curing agent was added to the mixed solution at a mass ratio of PDMS to curing agent of 10:1 and stirred evenly. The mixture was placed in a vacuum environment for 30 minutes to remove bubbles and obtain MWCNTs / PDMS prepolymer.

[0046] (3) Preparation of PDMS flexible driving film: The MWCNTs / PDMS prepolymer prepared in step (2) is spread evenly on the surface of a planar mold, and a film is formed by scraping with a 300μm coater. The film is then transferred to an 80℃ constant temperature oven and heated for 6 minutes to make it semi-cured. Then, the graphene paper prepared in step (1) is laid flat on the semi-cured MWCNTs / PDMS prepolymer, and a 200g weight is applied to make it adhere tightly together. The film is then heated at 80℃ for 4 hours to make it completely cured, thus obtaining the PDMS flexible driving film.

[0047] Example 3

[0048] A multi-stimulus responsive driven thin film and its preparation method are characterized by the following preparation steps:

[0049] (1) Preparation of graphene paper: Low-tack masking tape was uniformly applied along the fiber direction of A4 paper and peeled off at a constant speed to form a single-sided high-roughness surface on the A4 paper; the graphene aqueous dispersion was added at 4 mg / 25 cm⁻¹ 2 The loading amount is dripped onto the rough paper surface, spread evenly with a scraper, placed on a heating table and heated at 60°C for 2 hours to fully dry the moisture and flatten it to obtain a smooth graphene paper.

[0050] (2) Preparation of MWCNTs / PDMS prepolymer: 0.3g MWCNTs and 10g PDMS were dissolved in toluene and magnetically stirred for 10 minutes to mix them. The mixture was then ultrasonically treated at 300W for 1 hour to completely disperse the MWCNTs in the PDMS. The mixed solution was placed in an 80℃ constant temperature water bath stirring device and continuously treated at 300r / min for 4 hours. The curing agent was added to the mixed solution at a mass ratio of PDMS to curing agent of 10:1 and stirred evenly. The mixture was placed in a vacuum environment for 30 minutes to remove air bubbles and obtain the MWCNTs / PDMS prepolymer.

[0051] (3) Preparation of PDMS flexible driving film: The MWCNTs / PDMS prepolymer prepared in step (2) is spread evenly on the surface of a planar mold, and a film is formed by scraping with a 400μm coater. The film is then transferred to an 80℃ constant temperature oven and heated for 6 minutes to make it semi-cured. Then, the graphene paper prepared in step (1) is laid flat on the semi-cured MWCNTs / PDMS prepolymer, and a 200g weight is applied to make it adhere tightly together. The film is then heated at 80℃ for 4 hours to make it completely cured, thus obtaining the PDMS flexible driving film.

[0052] Example 4

[0053] A multi-stimulus responsive driven thin film and its preparation method are characterized by the following preparation steps:

[0054] (1) Preparation of graphene paper: Low-tack masking tape was uniformly applied along the fiber direction of A4 paper and peeled off at a constant speed to form a single-sided high-roughness surface on the A4 paper; the graphene aqueous dispersion was added at 8 mg / 25 cm⁻¹ 2 The loading amount is dripped onto the rough paper surface, spread evenly with a scraper, placed on a heating table and heated at 60°C for 2 hours to fully dry the moisture and flatten it to obtain a smooth graphene paper.

[0055] (2) Preparation of MWCNTs / PDMS prepolymer: 0.4g MWCNTs and 10g PDMS were dissolved in toluene and magnetically stirred for 10 minutes to mix them. The mixture was ultrasonically treated at 300W for 1 hour to completely disperse MWCNTs in PDMS. The mixed solution was placed in an 80℃ constant temperature water bath stirring device and continuously treated at 300r / min for 4 hours. The curing agent was added to the mixed solution at a mass ratio of PDMS to curing agent of 10:1 and stirred evenly. The mixture was placed in a vacuum environment for 30 minutes to remove bubbles and obtain MWCNTs / PDMS prepolymer.

[0056] (3) Preparation of PDMS flexible driving film: The MWCNTs / PDMS prepolymer prepared in step (2) is spread evenly on the surface of a planar mold, and a film is formed by scraping with a 500μm coater. The film is then transferred to an 80℃ constant temperature oven and heated for 6 minutes to make it semi-cured. Then, the graphene paper prepared in step (1) is laid flat on the semi-cured MWCNTs / PDMS prepolymer, and a 200g weight is applied to make it adhere tightly together. The film is then heated at 80℃ for 4 hours to make it completely cured, thus obtaining the PDMS flexible driving film.

[0057] The PDMS flexible actuation films prepared in Examples 2, 3, and 4 were subjected to bending actuation performance tests under light, temperature, and humidity stimulation. The test results were similar to those in Example 1.

Claims

1. A multi-stimulus responsive driven thin film and its preparation method, characterized in that... The preparation steps include the following: (1) Preparation of graphene paper: Use low-tack masking tape to evenly adhere along the direction parallel to the A4 paper fibers and perform a uniform peeling operation to form a single-sided high-roughness surface of the A4 paper; drop graphene aqueous dispersion onto the rough paper surface, spread evenly with a scraper, place on a heating table to dry the moisture and flatten to obtain a flat graphene paper. (2) Preparation of MWCNTs / PDMS prepolymer: MWCNTs and PDMS are dissolved in organic solvents and mixed. The mixture is ultrasonically treated to completely disperse MWCNTs in PDMS. The solvent is heated to evaporate completely. A curing agent is added to the mixed solution in proportion and stirred evenly to obtain MWCNTs / PDMS prepolymer. (3) Preparation of PDMS flexible driving film: The MWCNTs / PDMS prepolymer prepared in step (2) is spread evenly on the surface of a planar mold, coated into a film using a coater, and transferred to a constant temperature oven for heating to semi-cur. Then, the graphene paper prepared in step (1) is laid flat on the semi-cured MWCNTs / PDMS prepolymer, a weight is applied to make it adhere tightly together, and heating is continued to make it completely cured to obtain PDMS flexible driving film.

2. The multi-stimulus responsive driven thin film and its preparation method according to claim 1, characterized in that: In step (1), the concentration of the graphene aqueous dispersion is 2 mg / ml, and the drop volume is 2-8 mg / (25cm²). 2 ).

3. The multi-stimulus responsive driven thin film and its preparation method according to claim 1, characterized in that: In step (1), the drying temperature of the heating table is set to 60°C and the drying time is 4 hours.

4. The multi-stimulus responsive driven thin film and its preparation method according to claim 1, characterized in that: The organic solvent in step (2) includes at least one of toluene, n-hexane and propanol; MWCNTs include at least one of hydroxylated multi-walled carbon nanotubes, aminated multi-walled carbon nanotubes and pure carbon nanotubes.

5. The multi-stimulus responsive driven thin film and its preparation method according to claim 1, characterized in that: In step (2), the ultrasonic power is 300W and the ultrasonic time is 1h; the mass ratio of curing agent to PDMS is 1:

10.

6. The multi-stimulus responsive driven thin film and its preparation method according to claim 1, characterized in that: The thickness of the film formed by scraping in step (3) is 100-1000 μm.

7. The multi-stimulus responsive driven thin film and its preparation method according to claim 1, characterized in that: In step (3), the parameters of the semi-curing constant temperature oven are 80℃ for 5 minutes, and the parameters of the fully curing constant temperature oven are 80℃ for 360 minutes.

8. The flexible actuation film prepared by the preparation method according to any one of claims 1-7 and its application in the field of flexible robots.

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