Stretchable transparent tpu / ta film material, method of making and use thereof

Abstract

The application discloses a preparation method of stretchable transparent TPU / TA film material and belongs to the technical field of electrochemical energy storage. The preparation method comprises the following steps: dissolving thermoplastic polyurethane elastomer (TPU) and tannic acid (TA) in a mixed solution of acetone and DMF, heating and stirring in an oil bath, taking out after complete dissolution and cooling at room temperature; uniformly dropping and coating the obtained solution on a cleaned silicon wafer, taking off the TPU / TA film after evaporating the solvent; and finally performing gold spraying treatment. The application further discloses a stretchable transparent TPU / TA film material. As a flexible stretchable film, the TPU / TA film material has greatly improved light transmittance and tensile property, and gold is sprayed on the film so that the TPU / TA film material can be applied to a flexible current collector. In addition, the preparation process of the application is simple, the cost is low, the preparation period is short, the TPU / TA film material can be used as a current collector of a supercapacitor at any time, and the application of the TPU / TA film material promotes the application of the electrochemical energy storage field.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of electrochemical energy storage, and particularly relates to a stretchable transparent TPU / TA film material and a preparation method and application thereof. BACKGROUND

[0002] With the gradual popularity of integrated flexible wearable electronic products such as portable electronic devices, wearable electronic devices, microelectronic devices, printable electronic devices, smart textiles, skin electronics, etc., consumers have put forward higher and higher requirements for device performance, which also prompts researchers and related manufacturers in the field to continuously tap the potential of existing materials and strive to develop new high-performance materials. At present, many flexible wearable device researches are committed to integrating low cost, lightweight, stability, small size, flexibility and other attributes into flexible current collectors as an important branch of wearable devices. Therefore, manufacturing flexible transparent current collector films is crucial to transparent flexible supercapacitors, but it is difficult to obtain high transparency and high mechanical stretchability at the same time.

[0003] Thermoplastic polyurethane elastomer (TPU) is a (AB)n type block linear polymer composed of flexible soft segment and rigid hard segment, A is a polyester with a high molecular weight (1000-6000), B is a diol containing 2-12 straight-chain carbon atoms, and the chemical structure between AB segments is diisocyanate. As a kind of elastomer that can be plasticized by heating and dissolved by solvent, TPU has excellent comprehensive properties such as high strength, high toughness, wear resistance, oil resistance, good processing performance, and has become one of the important thermoplastic elastomer materials. Tannic acid (TA) is a polymer rich in hydroxyl groups, with 25 phenolic hydroxyl groups and 31 rotatable chemical bonds, which can make the molecule have good anisotropy. Current experiments have shown that TA with good biocompatibility can improve the performance of the gel.

[0004] To date, two strategies have been employed to increase the stretchability of equipment: one is to explore and adopt inherently flexible or stretchable materials; the other is to introduce stretchable substrates, enabling materials to possess excellent stretchability. Current technologies primarily utilize chemical vapor deposition (CVD) to prepare thin films, but films prepared by CVD are susceptible to contamination by other substances and are prone to defects. Some researchers have also used electrospinning to manufacture TPU films; however, while films prepared using this method possess certain stretchability, they lack optical transmittance. Furthermore, due to the inherent properties of the material, it lacks biocompatibility. During electrospinning, factors such as environment, voltage, flow rate, and receiving distance must be considered, resulting in low efficiency, and solvent recovery can also cause environmental pollution. (Breathable and Flexible Polymer Membranes with Mechanoresponsive Electric Resistance, Advanced Functional Materials, Volume 30, Issue 261907555; Metal–Phenolic Supramolecular Gelation, Angewandte Chemie International Edition, Volume55,Issue44p.13803-13807; DNA / TannicAcidHybridGelExhibitingBiodegradability,Extensibility,TissueAdhesiveness,andHemostaticAbility,AdvancedFunctionalMaterials, Volume25,Issue8p.1270-1278) Summary of the Invention

[0005] The purpose of this invention is to provide a stretchable transparent TPU / TA film material, its preparation method, and its application. The stretchable transparent TPU / TA film material of this invention improves the overall tensile properties of the thermoplastic polyurethane elastomer (TPU) after the addition of TA, and at the same time improves the light transmittance of the material, which can effectively prepare a flexible stretchable transparent film.

[0006] The objective of this invention is achieved through the following technical solution:

[0007] A method for preparing a stretchable transparent TPU / TA film material includes the following steps:

[0008] Step S1: Dissolve thermoplastic polyurethane elastomer (TPU) and tannic acid (TA) in a mixed solution of acetone and N,N-dimethylformamide (DMF), heat and stir in an oil bath, and remove and cool at room temperature after complete dissolution to obtain a mixed solution.

[0009] Step S2: Take the solution obtained in step S1 and uniformly drop it onto the cleaned silicon wafer, then heat the silicon wafer to evaporate the solvent dropped onto the silicon wafer, to obtain a solute film, and then peel it off with tweezers to obtain a TPU / TA film;

[0010] Step S3: Finally, perform gold spraying.

[0011] Furthermore, in step S1, the mass ratio of acetone to DMF in the mixed solution of acetone and DMF is 1:1.

[0012] Furthermore, the mass ratio of tannic acid (TA) to thermoplastic polyurethane elastomer (TPU) added in step S1 is 1:25-100.

[0013] Furthermore, the mass ratio of tannic acid (TA) to thermoplastic polyurethane elastomer (TPU) added in step S1 is 1:100.

[0014] Furthermore, the concentration of thermoplastic polyurethane elastomer (TPU) in the mixed solution obtained in step S1 is 2.4%-14.5%; the heating temperature of the oil bath in step S1 is 40°C, and the heating and stirring time is 5-7 hours.

[0015] Furthermore, the concentration of thermoplastic polyurethane elastomer (TPU) in the mixed solution obtained in step S1 is 3.6%.

[0016] Furthermore, step S2 specifically includes: using a microsyringe to draw 150 μL of the solution obtained in step S1 and uniformly drop it onto the cleaned silicon wafer, and placing it on a heating stage to evaporate the solvent; wherein the heating stage has a heating temperature of 40°C and a heating time of 8-10 h, and the silicon wafer has a size of 1.5 cm * 1.5 cm.

[0017] Furthermore, the gold spraying time in step S3 is 120 seconds.

[0018] Another object of the present invention is to provide a stretchable transparent TPU / TA film material, which is prepared by the above-described preparation method.

[0019] The present invention also discloses the application of the stretchable transparent TPU / TA film material as a flexible current collector film material.

[0020] The beneficial effects of this invention are as follows:

[0021] 1. The preparation method provided by this invention uses a heating and dissolving method to prepare a TPU / TA solution. After further adjusting the raw material ratio and controlling the reaction conditions and parameters, a stretchable transparent TPU / TA film material is prepared by evaporating the solvent. This method retains the stretchability of the original film and greatly improves the light transmittance of the film. Furthermore, the addition of TA improves the biocompatibility of the overall film by giving the molecules better anisotropy. All properties of the film are significantly improved, making it easier to apply to wearable devices. At the same time, the preparation method of this invention is simple, low-cost, quick to operate, and easy to recycle, making it suitable for widespread application.

[0022] 2. The stretchable transparent TPU / TA film prepared by the present invention, after gold plating, has a low resistance as a current collector film. Attached Figure Description

[0023] Figure 1 Optical transparency images of different volumes of the TPU / TA film prepared in Example 1;

[0024] Figure 2 Optical transparency diagrams of the TPU / TA film prepared in Example 1 at different concentrations;

[0025] Figure 3 This is an optical transparency diagram of the TPU / TA film prepared in Example 2;

[0026] Figure 4 The stress-strain curve of the TPU / TA film prepared in Example 2;

[0027] Figure 5 This is an optical transparency diagram of the TPU / TA film prepared in Example 2;

[0028] Figure 6 This is a side view of the contact angle of the TPU / TA film prepared in Example 2;

[0029] Figure 7 The resistivity diagram is shown for the thin film prepared in Example 3. Detailed Implementation

[0030] To enable those skilled in the art to better understand the content of this invention, the embodiments of this invention are described in detail below. These embodiments are implemented based on the technical solution of this invention, and provide detailed implementation methods and specific operation processes. However, the content of this invention is not limited to the following examples.

[0031] Example 1

[0032] Preparation of TPU / TA film materials

[0033] In this embodiment, the specific preparation process of the stretchable transparent TPU / TA film material is as follows:

[0034] 1) Prepare four solutions, A, B, C, and D: Take 0.16g of TPU and 0.0016g of TA into each culture bottle, and add 1.1g, 2.2g, 4.4g, and 6.6g of a mixed solution of DMF and acetone respectively (DMF:acetone = 1:1). Heat and stir at 40℃ for 4 hours to form clear solutions, and label them A, B, C, and D respectively.

[0035] 2) Take 50, 100, 150 and 200 μL of solution C and drop it onto a 1.5cm*1.5cm silicon wafer, then place it on a heating stage at 40℃ to evaporate the solvent. After 8 hours, a transparent film is formed.

[0036] 3) Take 150 μL of each of the four solutions A, B, C, and D and drop them onto a 1.5 cm * 1.5 cm silicon wafer. Then place the wafer on a heating stage at 40 °C to evaporate the solvent. After 8 hours, a transparent film will be formed.

[0037] Figure 1 These are optical transparency images of different volumes of the TPU / TA film prepared in this embodiment, as shown below. Figure 1 As shown, when the solution volume is 150 μL, the film thickness is about 20 μm and the optical transmittance is 81%.

[0038] Figure 2 The images show the optical transparency of the TPU / TA film prepared in this embodiment at different concentrations, as shown below. Figure 2 As shown, when the volume of solution C is 150 μL, the film thickness is 17.49 μm and the optical transmittance is 81%.

[0039] In summary, the sample prepared in this embodiment has good optical transparency, with a transmittance of 81% at 550 nm.

[0040] Example 2

[0041] 1) Prepare five solutions and label them A, B, C, D, and E: A contains 0.16g TPU, 4.4g DMF, and acetone (DMF:acetone = 1:1); B contains 0.16g TPU, 0.0016g TA, and 4.4g DMF and acetone (DMF:acetone = 1:1); C contains 0.1595g TPU, 0.0021g TA, and 4.4g DMF... F is a mixed solution of DMF and acetone (DMF:acetone = 1:1), D contains 0.1584g TPU, 0.0032g TA, and 4.4g of a mixed solution of DMF and acetone (DMF:acetone = 1:1), and E contains 0.1554g TPU, 0.0062g TA, and 4.4g of a mixed solution of DMF and acetone (DMF:acetone = 1:1). All are heated and stirred at 40°C for 4 hours to form a transparent solution.

[0042] 2) Take 150 μL of each of the above solutions and drop them onto a 1.5 cm * 1.5 cm silicon wafer. Then place it on a heating stage at 40 °C to evaporate the solvent. After 8 hours, a transparent film is formed.

[0043] Figure 3 The figure shows the optical transparency of the TPU / TA film prepared in this embodiment. When the mass of TPU is 0.16g and the mass of TA is 0.0016g, the transmittance of the prepared film is optimal, which is 81%.

[0044] Figure 4 The stress-strain curve of the TPU / TA film prepared in this embodiment is shown in the figure. When the mass of TPU is 0.16g and the mass of TA is 0.0016g, the tensile properties of the prepared film are optimal, and the strain can reach 300%.

[0045] Figure 5 The image shows the optical transparency of the TPU / TA film prepared in this embodiment. As shown, after reaching the maximum strain, the transmittance of the TPU / TA film decreases slightly to 78%.

[0046] Figure 6 The contact angle of the TPU / TA film prepared in this embodiment is tested. The contact angle is approximately 90°, indicating that it is a hydrophobic film.

[0047] In summary, the sample prepared in this embodiment also has good optical transparency and good tensile properties.

[0048] Example 3

[0049] In this embodiment, the preparation methods of solutions A, B, C, D, and E are the same as in Example 2. Then, the thin film prepared with solution B is sputtered with gold for 0s, 30s, and 120s, respectively. The resistance of the flexible current collector thin film obtained after the above treatment is as follows: Figure 7As shown, the resistance of the thin film is only 34.7 Ω at 120 s. Therefore, the sample prepared in this embodiment also has a low resistance.

[0050] Experiments have shown that TPU / TA films prepared by solvent evaporation exhibit high optical transparency and good tensile properties. After gold plating, the films, when used as current collectors, have low resistance. Furthermore, the preparation method of these films is simple, the production cost is low, the application is convenient and quick, and they are easily recyclable, making them suitable for widespread application.

[0051] The above description is only a preferred embodiment of the present invention and is not limited to the above implementation method. Any equivalent modifications, substitutions and improvements made by those skilled in the art based on the content disclosed in the present invention should be included in the protection scope of the claims.

Claims

1. A method for preparing a stretchable transparent TPU / TA film material, characterized in that, Includes the following steps: Step S1: Dissolve thermoplastic polyurethane elastomer (TPU) and tannic acid (TA) in a mixed solution of acetone and N,N-dimethylformamide (DMF). Heat and stir in an oil bath until completely dissolved, then remove and cool at room temperature to obtain a mixed solution. The mass ratio of tannic acid (TA) to thermoplastic polyurethane elastomer (TPU) is 1:25-100. The concentration of thermoplastic polyurethane elastomer (TPU) in the resulting mixed solution is 2.4%-14.5%. Step S2: Take the solution obtained in step S1 and uniformly drop it onto the cleaned silicon wafer, then heat the silicon wafer to evaporate the solvent dropped onto the silicon wafer, thus obtaining a solute film, namely a TPU / TA film. Step S3: Finally, perform gold spraying.

2. The method for preparing the stretchable transparent TPU / TA film material according to claim 1, characterized in that, In step S1, the mass ratio of acetone to DMF in the mixed solution of acetone and DMF is 1:

1.

3. The method for preparing the stretchable transparent TPU / TA film material according to claim 1, characterized in that, The mass ratio of tannic acid (TA) to thermoplastic polyurethane elastomer (TPU) added in step S1 is 1:

100.

4. The method for preparing the stretchable transparent TPU / TA film material according to claim 1, characterized in that, In step S1, the oil bath is heated to 40°C and the heating and stirring time is 5-7 hours.

5. The method for preparing the stretchable transparent TPU / TA film material according to claim 1, characterized in that, The concentration of thermoplastic polyurethane elastomer (TPU) in the mixed solution obtained in step S1 is 3.6%.

6. The method for preparing the stretchable transparent TPU / TA film material according to claim 1, characterized in that, Step S2 specifically includes: using a microsyringe to draw 150 μL of the solution obtained in step S1 and uniformly drop it onto the cleaned silicon wafer, and placing it on a heating stage to evaporate the solvent; wherein the heating stage has a heating temperature of 40°C and a heating time of 8-10 h, and the silicon wafer has a size of 1.5 cm × 1.5 cm.

7. The method for preparing the stretchable transparent TPU / TA film material according to claim 1, characterized in that, The gold spraying time in step S3 is 120 seconds.

8. A stretchable transparent TPU / TA film material, characterized in that, It is prepared by the preparation method according to any one of claims 1-7.

9. The application of the stretchable transparent TPU / TA film material according to claim 8 as a flexible current collector film material.

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