Optically driven flexible thin film, method of making and use in marine power systems

Abstract

This invention discloses a light-driven flexible thin film, its preparation method, and its application in ship propulsion systems, belonging to the field of light-driven flexible thin films. The preparation method includes the following steps: (1) pretreatment of cellulose paper; (2) preparation of a nano-photothermal material / cellulose bilayer film; (3) preparation of a nano-photothermal material / cellulose / polyimide trilayer film actuator. Beneficial effects: This invention cleverly combines nano-photothermal materials, cellulose paper materials, and polyimide materials to obtain a light-driven flexible trilayer film material with extremely fast response speed and stable vibration amplitude. After hundreds of thousands of cycles, its performance shows almost no decay, exhibiting extremely high stability. The preparation process is simple, the response speed is fast, and the working efficiency is improved. It can simplify the ship propulsion system, reduce a large number of propulsion systems, shaft devices, and fuel reserves, greatly reduce the ship's load, and allow it to move forward continuously under light source illumination.

Description

Technical Field

[0001] This invention relates to the field of light-driven flexible thin film technology, specifically to a light-driven flexible thin film, its preparation method, and its application in ship propulsion systems. Background Technology

[0002] Ships are common means of transportation with many uses. They can serve as bridges across smaller rivers and transport goods on vast oceans. Due to their unique structure and transportation principles, ships can carry far more cargo than ordinary vehicles or airplanes thanks to buoyancy. Therefore, ships are often used for transporting oversized cargo. Correspondingly, ships require a huge energy supply during transport. Ordinary ships often use diesel fuel as their primary fuel, converting the energy in the fuel into mechanical energy to drive the propeller at high speed through a heat engine. The high-speed rotation of the propeller and the water-pushing blades then propel the ship forward. However, the energy conversion efficiency of heat engines is relatively low, and energy is constantly lost during transmission. The entire process involves significant energy loss and consumes a large amount of energy.

[0003] Current ships require various power systems, pivoting devices, and fuel reserves to transport cargo and move forward continuously. This results in existing ships being large in size, failing to maximize the cargo-to-cargo ratio, having complex structural designs, and high costs. However, to enable ships to transport large amounts of cargo and move forward continuously without numerous power systems, pivoting devices, and fuel reserves, the key lies in developing a flexible material that can be driven by light. This would avoid the complex system design required by power systems, pivoting devices, and fuel reserves, while simultaneously allowing for continuous movement and carrying more cargo based on the light source.

[0004] Chinese patent application CN115403807A discloses a photothermal actuation film, its preparation method, and its applications. The film has a bilayer structure with a total thickness of 35-50 μm. Along its thickness, from one surface to a thickness of 15-25 μm, it is composed of a polymer. The remaining thickness consists of the polymer and a photothermal filler uniformly dispersed within the polymer. The mass ratio of the polymer to the filler is (70-97):(3-30). The polymer has a high coefficient of thermal expansion, while the filler has a low coefficient of thermal expansion. This patented photothermal actuation film has a simple structure, is easy to prepare, and has a fast response speed, making it suitable for applications such as flexible robots and biomimetic systems. However, the film preparation process is complex, and the response speed is relatively slow, thus requiring further improvement. Summary of the Invention

[0005] The technical problem to be solved by this invention is how to solve the problems of complex preparation process, slow response speed and inability to oscillate independently and stably in existing light-driven flexible thin films.

[0006] The present invention solves the above-mentioned technical problems through the following technical means:

[0007] The first aspect of this invention provides a method for preparing a light-driven flexible thin film, comprising the following steps:

[0008] (1) Pretreatment of cellulose paper: Apply polypropylene (BOPP) tape to one side of the cellulose paper, stick it tightly, and then quickly peel it off to remove a thin layer from the surface, resulting in cellulose paper with one side being relatively rough and the other side being relatively smooth.

[0009] (2) Preparation of nano-photothermal material / cellulose bilayer film: MXene solution is dripped onto the rough side of the cellulose paper treated in step (1), evenly coated, dried, sandwiched between two clean glass plates, and pressed down with a heavy object to stand, so as to obtain a flat nano-photothermal material / cellulose bilayer film.

[0010] (3) Preparation of nanophotothermal material / cellulose / polyimide three-layer film actuator: The side of the nanophotothermal material / cellulose bilayer film without MXene deposition is pasted onto polyimide tape to obtain the nanophotothermal material / cellulose / polyimide three-layer film actuator.

[0011] Beneficial effects: This invention cleverly combines nano-photothermal materials, cellulose paper materials, and polyimide materials to prepare a light-driven flexible three-layer film material with extremely fast response speed and stable vibration amplitude. After hundreds of thousands of cycles, its performance has almost no decay and it has extremely high stability. The preparation process is simple, the response speed is fast, and the work efficiency is improved.

[0012] Preferably, the cellulose paper in step (1) is a commercial A4 carbon paper, cardstock, or other cellulose film.

[0013] Beneficial effects: Commercial A4 carbon paper is composed of a cellulose fiber network structure. Because the surface of cellulose has hydrophilic functional groups (-OH and -O), it can easily absorb water molecules from the surrounding environment and expand. Once heated, the water molecules adsorbed in the paper will desorb, causing the paper to shrink and deform. Thus, it can produce reversible volume changes under the stimulation of humidity or temperature. Therefore, paper containing a large amount of cellulose exhibits a high hygroscopic expansion coefficient (CHE≈0.1C-1) and a low thermal expansion coefficient.

[0014] Preferably, in step (2), the concentration of MXene solution is 1-5 mg / mL, the required solution is 2-8 mL, and the hot pressing time is 4-8 h.

[0015] Preferably, in step (2), MXene is Ti3C2TX, and the MXene layer has a stacked layered structure inside.

[0016] Preferably, in step (2), the thickness of the MXene film is 3 to 10 μm; and the thickness of the cellulose paper is 30 to 100 μm.

[0017] Beneficial effects: MXene is a two-dimensional layered material with excellent photothermal conversion ability and good thermal conductivity. At the same time, due to the presence of water molecules between the layers, the MXene film will shrink and deform due to water loss when the temperature rises, making it a very good light-driven material.

[0018] Preferably, the thickness of the polyimide tape in step (3) is 40-60 μm.

[0019] Beneficial effects: Polyimide is a polymer material widely used in industrial fields. It has a high coefficient of thermal expansion (CTE is about 2.8×10-5 / ℃) and a negligible coefficient of hygroscopic expansion (CHE), as well as certain mechanical strength and good chemical stability.

[0020] Preferably, the bending angle of the light-driven flexible film when it is stationary is in the range of 10 to 60°.

[0021] A second aspect of the present invention proposes a light-driven flexible thin film prepared using the above-described preparation method.

[0022] A third aspect of the present invention proposes the application of the light-driven flexible thin film prepared by the above preparation method in a ship propulsion system.

[0023] Preferably, the application specifically involves using a light-driven flexible film as a motor to drive a biomimetic paddle to continuously oscillate and propel water, providing forward power for the vessel.

[0024] The advantages of this invention are:

[0025] 1. This invention cleverly combines nano-photothermal materials, cellulose paper materials, and polyimide materials to prepare a light-driven flexible three-layer film material with extremely fast response speed and stable vibration amplitude. After hundreds of thousands of cycles, its performance has almost no decay and it has extremely high stability. The preparation process is simple, the response speed is fast, and the work efficiency is improved.

[0026] 2. The light-driven flexible film prepared by this invention greatly simplifies the ship's propulsion system, eliminating a large number of propulsion systems, shaft devices, and fuel reserves, thus greatly reducing the ship's load. Moreover, it can continue to move forward under the illumination of a light source, and the energy used is a light source, which is readily available and pollution-free. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the preparation of the nano-photothermal material / cellulose / polyimide light-driven flexible three-layer film (i.e., light-driven flexible film) in Example 1 of the present invention;

[0028] Figure 2 This is a schematic diagram of the bending deformation of the light-driven flexible film under laser irradiation in Embodiment 1 of the present invention;

[0029] Figure 3 The figure shows the performance test results of the light-driven flexible thin film in Embodiment 1 of the present invention. Figure 3 (a) shows the oscillation amplitude results of the thin film. Figure 3 (b) shows the oscillation frequency results of the thin film;

[0030] Figure 4 This is a schematic diagram of the ship propulsion system designed based on a light-driven thin film in Embodiment 1 of the present invention, which can provide forward thrust through continuous autonomous vibration under illumination;

[0031] In the figure: 1. Cellulose paper; 2. Nanophotothermal material / cellulose bilayer film; 3. Polyimide tape (PI); 4. Polymer film; 5. Bionic paddle; 6. Laser light; 7. Stern support. Detailed Implementation

[0032] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0033] Unless otherwise specified, all test materials and reagents used in the following examples are commercially available.

[0034] Unless otherwise specified in the embodiments, the techniques or conditions described in the literature in this field or in accordance with the product manual may be followed.

[0035] Example 1:

[0036] A method for preparing a light-driven flexible thin film includes the following steps:

[0037] (1) Pretreatment of cellulose paper: Apply polypropylene (BOPP) tape to one side of commercial A4 carbon paper, and peel it off quickly after it is firmly attached. This will peel off a thin layer of the surface and give you cellulose paper with one side being relatively rough and the other side being relatively smooth.

[0038] (2) Preparation of nano-photothermal material / cellulose bilayer film: 5 mL of MXene dispersion (MXene is Ti3C2TX, solution concentration is 3 mg / mL) was dripped onto the rough side of the treated cellulose paper and evenly coated on the paper. Then, it was placed on a heating platform to dry. The cellulose paper with MXene deposited was sandwiched between two clean glass plates and placed on the heating platform and pressed down with a heavy object for 6 h to obtain a smooth nano-photothermal material / cellulose bilayer film (MXene film thickness is 6 μm; the cellulose paper thickness is 50 μm).

[0039] (3) Preparation of nanophotothermal material / cellulose / polyimide three-layer film actuator: The side of the nanophotothermal material / cellulose bilayer film without MXene deposition is pasted onto polyimide tape (the thickness of the polyimide tape is 50μm) to obtain the nanophotothermal material / cellulose / polyimide three-layer film actuator.

[0040] Figure 1 This is a schematic diagram illustrating the fabrication of the nano-photothermal material / cellulose / polyimide light-driven flexible three-layer film (i.e., light-driven flexible film) in this embodiment;

[0041] The performance of the nano-photothermal material / cellulose / polyimide three-layer thin film actuator (i.e., light-driven flexible film) prepared in this embodiment was tested under laser to verify the cyclic stability of the thin film actuator under laser stimulation with constant output power.

[0042] Figure 2 This is a schematic diagram of the bending deformation of the light-driven flexible film under laser irradiation in this embodiment;

[0043] Test results are as follows Figure 3 As shown, the thin-film actuator oscillated continuously for 120,320 cycles at an average oscillation frequency of 6.36 Hz, with an oscillation time of approximately 5.14 hours. Within each oscillation cycle, the response time of the thin-film actuator was approximately 0.078 s. The amplitude at the start and end of the oscillation of the thin-film actuator during the entire self-oscillation process was measured, as follows: Figure 3 As shown in (a), it can be seen that the amplitude of the thin-film actuator did not change significantly after more than 5 hours of self-oscillation. Furthermore, the frequency change of the thin-film actuator every 100 seconds during the entire self-oscillation process was also tested, as follows: Figure 3 As shown in (b), the thin-film driver has a frequency of approximately 6.32 Hz at the beginning of oscillation and approximately 6.38 Hz at the end of oscillation, without producing large frequency fluctuations.

[0044] In summary, the self-oscillation performance of the thin-film actuator did not show significant degradation throughout the entire cyclic stability test, indicating that the continuous self-oscillation generated by the thin-film actuator under constant laser stimulation has good cyclic stability. This provides a foundation for the application development of this thin-film actuator based on self-oscillating motion in ship propulsion systems. It is worth noting that due to equipment limitations, the cyclic stability test was only conducted for a little over 5 hours. Therefore, it is speculated that the cyclic stability time of the actuator's self-oscillating motion is even longer. When applied to ship propulsion systems, it can propel ships forward with a stable frequency and amplitude.

[0045] Example 2:

[0046] A method for preparing a light-driven flexible thin film includes the following steps:

[0047] (1) Pretreatment of cellulose paper: Apply polypropylene (BOPP) tape to one side of commercial A4 carbon paper, and peel it off quickly after it is firmly attached. This will peel off a thin layer of the surface and give you cellulose paper with one side being relatively rough and the other side being relatively smooth.

[0048] (2) Preparation of nano-photothermal material / cellulose bilayer film: 2 mL of MXene dispersion (MXene is Ti3C2TX, solution concentration is 1 mg / mL) was dripped onto the rough side of the treated cellulose paper and evenly coated on the paper. Then, it was placed on a heating platform to dry. The cellulose paper with MXene deposited was sandwiched between two clean glass plates and placed on the heating platform and pressed down with a weight for 4 h to obtain a smooth nano-photothermal material / cellulose bilayer film (MXene film thickness is 3 μm; the cellulose paper thickness is 30 μm).

[0049] (3) Preparation of nanophotothermal material / cellulose / polyimide three-layer film actuator: The side of the nanophotothermal material / cellulose bilayer film without MXene deposition is pasted onto polyimide tape (the thickness of the polyimide tape is 40μm) to obtain the nanophotothermal material / cellulose / polyimide three-layer film actuator.

[0050] Example 3:

[0051] A method for preparing a light-driven flexible thin film includes the following steps:

[0052] (1) Pretreatment of cellulose paper: Apply polypropylene (BOPP) tape to one side of commercial A4 carbon paper, and peel it off quickly after it is firmly attached. This will peel off a thin layer of the surface and give you cellulose paper with one side being relatively rough and the other side being relatively smooth.

[0053] (2) Preparation of nano-photothermal material / cellulose bilayer film: 8 mL of MXene dispersion (MXene is Ti3C2TX, solution concentration is 5 mg / mL) was dripped onto the rough side of the treated cellulose paper and evenly coated on the paper. Then, it was placed on a heating platform to dry. The cellulose paper with MXene deposited was sandwiched between two clean glass plates and placed on the heating platform and pressed down with a heavy object for 8 h to obtain a smooth nano-photothermal material / cellulose bilayer film (MXene film thickness is 10 μm; the cellulose paper thickness is 80 μm).

[0054] (3) Preparation of nanophotothermal material / cellulose / polyimide three-layer film actuator: The side of the nanophotothermal material / cellulose bilayer film without MXene deposition is pasted onto polyimide tape (the thickness of the polyimide tape is 60μm) to obtain the nanophotothermal material / cellulose / polyimide three-layer film actuator.

[0055] The performance of the nano-photothermal material / cellulose / polyimide three-layer thin film actuators (i.e., light-driven flexible films) prepared in Examples 2 and 3 was tested under laser, and the test results were similar to those in Example 1.

[0056] Example 4:

[0057] A ship propulsion system based on a light-driven thin film design, capable of providing forward thrust through continuous autonomous vibration under illumination, includes a light source, a light-driven flexible thin film prepared in Example 1, and a biomimetic paddle. The light source is a laser lamp or optical fiber, connected to a power source via wires and powered by a battery. A laser lamp regulator controls the laser's on / off state and intensity. The paddle is made by connecting the light-driven thin film material to biomimetic blades, using the light-driven flexible thin film as a motor. When stimulated by the light source, the light-driven thin film material drives the biomimetic paddles to continuously oscillate and propel the water, providing forward thrust for the ship.

[0058] The light-driven polymer film material was glued to the stern of the boat. Then, wires were threaded through the holes in the hull to connect the laser light to the laser light dimmer. The power supply and dimmer circuit were then connected. Finally, the laser light was mounted on the tail fin, completing the construction of a boat propulsion system that can continuously vibrate autonomously under light to provide forward thrust.

[0059] like Figure 1 The diagram shows the fabrication process of a light-driven flexible three-layer film (nanophotothermal material / cellulose / polyimide). Figure 2The light-driven principle of a nano-photothermal material / cellulose / polyimide three-layer film is presented: Polyimide (PI) is a polymer material widely used in industrial fields. It has a high coefficient of thermal expansion (CTE approximately 2.8 × 10⁻⁵ / ℃) and a negligible coefficient of hygroscopic expansion (CHE), as well as certain mechanical strength and good chemical stability. Paper is composed of a cellulose fiber network structure. Due to the hydrophilic functional groups (-OH and -O) on the surface of cellulose, it easily absorbs water molecules from the surrounding environment and expands. Once heated, the water molecules adsorbed in the paper will desorb, causing the paper to shrink and deform. Thus, it can produce reversible volume changes under the stimulation of humidity or temperature. Therefore, paper containing a large amount of cellulose exhibits a high coefficient of hygroscopic expansion (CHE≈0.1C⁻¹) and a low coefficient of thermal expansion.

[0060] MXene, a novel two-dimensional nanomaterial, possesses excellent conductivity, hydrophilicity, and outstanding photothermal conversion efficiency. Therefore, in a flexible actuator with a three-layer structure of nano-photothermal material / cellulose / polyimide, MXene serves as the photothermal / electrothermal conversion layer, while cellulose paper and PI act as the main driving active units. When the actuator is exposed to light or when voltage is applied, MXene converts light / electric energy into heat energy through the photothermal / Joule heating effect and conducts it. Due to the difference in CTE between PI and cellulose paper, the PI layer undergoes thermal expansion, while the paper shrinks in volume. This asymmetric volume change causes the nano-photothermal material / cellulose / polyimide film actuator to bend and deform towards the MXene side. When the actuator is stimulated by humidity, in addition to the cellulose paper absorbing water molecules from the air and expanding, MXene also undergoes water molecule intercalation under increased humidity, leading to volume expansion. PI, however, shows no change in its humidity response. Therefore, the nano-photothermal material / cellulose / polyimide film actuator bends and deforms towards the PI side. In addition, MXene exhibits dehydration behavior when heated, which leads to a reduction in the interlayer spacing of MXene nanosheets and volume shrinkage, thus facilitating the bending deformation of the co-actuator under photothermal / electrothermal conditions.

[0061] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing a light-driven flexible thin film, characterized in that, Includes the following steps: (1) Pretreatment of cellulose paper: Polypropylene tape is attached to one side of the cellulose paper. After it is firmly attached, it is quickly peeled off to remove a thin layer of the surface, resulting in cellulose paper with one side being relatively rough and the other side being relatively smooth. (2) Preparation of nano-photothermal material / cellulose bilayer film: MXene solution is dripped onto the rough side of the cellulose paper treated in step (1), evenly coated, dried, sandwiched between two clean glass plates, and pressed down with a heavy object to stand, so as to obtain a flat nano-photothermal material / cellulose bilayer film. (3) Preparation of nanophotothermal material / cellulose / polyimide three-layer film actuator: The side of the nanophotothermal material / cellulose bilayer film without MXene deposition is pasted onto polyimide tape to obtain the nanophotothermal material / cellulose / polyimide three-layer film actuator.

2. The method for preparing a light-driven flexible thin film according to claim 1, characterized in that, In step (1), the cellulose paper is commercial A4 carbon paper or cardstock.

3. The method for preparing a light-driven flexible thin film according to claim 1 or 2, characterized in that, In step (2), the concentration of MXene solution is 1-5 mg / mL, the required solution is 2-8 mL, and the hot pressing time is 4-8 h.

4. The method for preparing a light-driven flexible thin film according to claim 3, characterized in that, In step (2), MXene is Ti3C2TX, and the MXene layer has a stacked layered structure inside.

5. The method for preparing a light-driven flexible thin film according to claim 4, characterized in that, In step (2), the thickness of the MXene film is 3 to 10 μm; the thickness of the cellulose paper is 30 to 100 μm.

6. The method for preparing a light-driven flexible thin film according to claim 1, characterized in that, The thickness of the polyimide tape in step (3) is 40~60μm.

7. The method for preparing a light-driven flexible thin film according to claim 1, characterized in that, The bending angle of the light-driven flexible film when it is stationary is in the range of 10 to 60°.

8. A light-driven flexible thin film prepared by the preparation method according to any one of claims 1-7.

9. The application of the light-driven flexible thin film prepared by the preparation method according to any one of claims 1-7 in a ship propulsion system.

10. The application according to claim 9, characterized in that, The specific application is as follows: using a light-driven flexible film as a motor to drive a biomimetic paddle to continuously swing and propel water, providing forward power for the boat.

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