CN113637181B - Polyvinyl alcohol-based conductive hydrogel and preparation method and application thereof - Google Patents

Abstract

The invention discloses a polyvinyl alcohol-based conductive hydrogel and a preparation method and application thereof, wherein the preparation method of the polyvinyl alcohol-based conductive hydrogel comprises the following steps of 1, mixing and uniformly dispersing PVA aqueous solution, ethylene glycol, PEDOT, PSS, sodium polyacrylate and deionized water, and then standing to eliminate bubbles to obtain uniformly mixed solution; and 2, casting the mixed solution prepared in the step 1 into a mould or a container, repeatedly freezing and unfreezing, and then soaking in a saturated sodium chloride solution for 0-24 hours to obtain the polyvinyl alcohol-based conductive hydrogel.

Description

A kind of polyvinyl alcohol-based conductive hydrogel and its preparation method and application

technical field

The invention belongs to the field of chemical materials, and in particular relates to a polyvinyl alcohol-based conductive hydrogel and a preparation method and application thereof.

Background technique

Conductive hydrogels combine the flexible properties of hydrogels with the electrical properties of conductive materials, and have potential applications in electronic skin, flexible sensors, and new energy batteries. However, it is still a challenge to prepare conductive hydrogels with good mechanical properties and high electrical conductivity. In recent years, polyvinyl alcohol (PVA) hydrogels have been widely used due to their good mechanical properties, biocompatibility, and environmental friendliness. And contains more active hydroxyl groups, making it one of the ideal substrates for the preparation of conductive hydrogels. However, polyvinyl alcohol hydrogels have poor electrical conductivity, and methods such as doping conductive fillers and conductive polymers are needed to prepare high-conductivity hydrogels. The commonly used conductive media for conductive hydrogels include conductive fillers such as carbon nanotubes, graphene, etc., conductive polymers such as polyaniline, polypyrrole, PEDOT:PSS, etc. Among them, PEDOT:PSS has been used more in the field of flexible sensing in recent years. A water-soluble conductive polymer dopant. However, the conductivity of PEDOT:PSS-doped conductive hydrogels is limited by the insulator PSS. Solvent exfoliation and π-π interaction are usually used to exfoliate PSS to improve the conductivity of PEDOT:PSS.

SUMMARY OF THE INVENTION

In order to solve the above technical problems, the purpose of the present invention is to provide a preparation method of a polyvinyl alcohol-based conductive hydrogel with good mechanical properties and electrical conductivity.

In order to achieve the above object, the technical scheme of the present invention is as follows: a preparation method of a polyvinyl alcohol-based conductive hydrogel, comprising the following steps:

Step 1: get the PVA aqueous solution, ethylene glycol, PEDOT:PSS, sodium polyacrylate and deionized water to mix and disperse uniformly, then stand to eliminate air bubbles to obtain a well-mixed mixed solution;

Step 2: Cast the mixed solution prepared in Step 1 in a mold or container, and freeze and thaw repeatedly, and then soak it in a saturated sodium chloride solution for 0-24 hours to obtain a polyvinyl alcohol-based conductive hydrogel .

Preferably, in the step 1, the mass ratio of the PVA aqueous solution, ethylene glycol, PEDOT:PSS, sodium polyacrylate and deionized water is 100-300:0-3:0-30:0-1:0-30.

Preferably, the concentration of the PVA aqueous solution is 7.5-12.5 wt %, and the PVA is one or a mixture of PVA-1799, PVA-1788 and PVA-2099.

Preferably, the solid content of the PEDOT:PSS is 1.0%-1.3%.

Preferably, the weight average molecular weight of the sodium polyacrylate is 3 million-7 million.

Preferably, in the step 1, the dispersion is uniformly dispersed at room temperature with a high-speed disperser. less than 6h.

Preferably, in the step 2, the freezing temperature is -20°C-0°C, the freezing time is 20 hours each time, the thawing temperature is 20°C-30°C, the thawing time is 4 hours each time, and the freezing and thawing time is 4 hours. The number of cycles is 3-5 times.

Another object of the present invention is to provide a polyvinyl alcohol-based conductive hydrogel prepared by the above-mentioned preparation method of a polyvinyl alcohol-based conductive hydrogel.

The third object of the present invention is to provide an application of the above-mentioned polyvinyl alcohol-based conductive hydrogel in artificial skin, flexible tension sensor or supercapacitor.

The beneficial effects of the present invention are as follows: the present invention uses PEDOT:PSS as the conductive medium, sodium polyacrylate as the dopant, water and ethylene glycol as the solvent, and polyvinyl alcohol as the matrix, through a cyclic freeze-thaw method and a salt solution The conductive hydrogel with excellent mechanical properties and electrical conductivity is obtained by the soaking method. The present invention significantly improves the tensile properties and properties of the hydrogel by simultaneously introducing dopants sodium polyacrylate and ethylene glycol and soaking with a saturated sodium chloride solution. In addition, the preparation method of the present invention is simple, the raw materials are easily obtained, and the prepared conductive hydrogel has potential application prospects in the fields of artificial skin, flexible stress sensor or super capacitor.

Description of drawings

FIG. 1 is a graph of the resistance change of the vinyl alcohol-based conductive hydrogel corresponding to Example 3 of the present invention when it is deformed.

Detailed ways

The present invention will be further described in detail below with reference to the examples, and the examples are only used to explain the present invention, and are not intended to limit the scope of the present invention.

Example 1

The present embodiment provides a preparation method of a polyvinyl alcohol-based conductive hydrogel, and the preparation steps are as follows:

Step 1: Add 20g of PVA-1799 solution with a concentration of 10wt%, 0.25g of ethylene glycol, and 2.5g of deionized water into a 50mL beaker, disperse with a high-speed disperser for 5min at room temperature, and let stand for 12h to eliminate air bubbles to obtain a mixed solution. homogeneous mixed solution;

Step 2: Cast the mixed solution obtained in step 1 into a mold, freeze at -20°C for 20 hours, and then thaw at 20°C for 4 hours, repeat the above freezing and thawing process 3 times to obtain a polyvinyl alcohol-based conductive hydrogel .

Example 2

The present embodiment provides a preparation method of a polyvinyl alcohol-based conductive hydrogel, and the preparation steps are as follows:

Step 1: Add 20g of PVA-1788 solution with a concentration of 10wt%, 0.25g of ethylene glycol and 2.5g of PEDOT:PSS with a concentration of 1.0wt% into a 50mL beaker, disperse with a high-speed disperser at room temperature for 5min, and let stand for 12h Eliminate air bubbles to obtain a homogeneous mixed solution;

Step 2: Cast the mixed solution obtained in step 1 into a mold, freeze at -20°C for 20 hours, and then thaw at 20°C for 4 hours, repeat the above freezing and thawing process 3 times to obtain a polyvinyl alcohol-based conductive hydrogel .

Example 3

The present embodiment provides a preparation method of a polyvinyl alcohol-based conductive hydrogel, and the preparation steps are as follows:

Step 1: Add 20 g of PVA-1788 solution with a concentration of 10 wt %, 0.25 g of ethylene glycol, 2.5 g of PEDOT:PSS with a concentration of 1.0 wt % and 0.02 g of sodium polyacrylate into a 50 mL beaker. Disperse in the device for 5min, let stand for 12h to eliminate air bubbles, and obtain a homogeneous mixed solution;

Step 2: Cast the mixed solution obtained in Step 1 into a mold, freeze at -20°C for 20 hours, then thaw at 20°C for 4 hours, and repeat the above freezing and thawing process 4 times to obtain a polyvinyl alcohol-based conductive hydrogel .

Example 4

The present embodiment provides a preparation method of a polyvinyl alcohol-based conductive hydrogel, and the preparation steps are as follows:

Step 1: Add 20g of PVA-1788 solution with a concentration of 10wt%, 0.25g of ethylene glycol (EG) solvent and 2.5g of deionized water into a 50mL beaker, disperse with a high-speed disperser for 5min at room temperature, and let stand for 12h to eliminate air bubbles to obtain a uniform mixed solution;

Step 2: Cast the mixed solution obtained in Step 1 into a mold, freeze at -20°C for 20 hours, then thaw at 20°C for 4 hours, repeat the above freezing and thawing process 3 times, and then place in saturated sodium chloride solution Soak in 24h to obtain polyvinyl alcohol-based conductive hydrogel.

Example 5

The present embodiment provides a preparation method of a polyvinyl alcohol-based conductive hydrogel, and the preparation steps are as follows:

Step 1: Add 20g of PVA-1799 solution with a concentration of 10wt%, 0.25g of ethylene glycol and 2.5g of PEDOT:PSS with a concentration of 1.0wt% into a 50mL beaker, disperse with a high-speed disperser at room temperature for 5min, and let stand for 12h Eliminate air bubbles to obtain a homogeneous mixed solution;

Step 2: Cast the mixed solution obtained in Step 1 into a mold, freeze at -20°C for 20 hours, then thaw at 20°C for 4 hours, repeat the above freezing and thawing process 3 times, and then place in saturated sodium chloride solution Soak in 24h to obtain polyvinyl alcohol-based conductive hydrogel.

Example 6

The present embodiment provides a preparation method of a polyvinyl alcohol-based conductive hydrogel, and the preparation steps are as follows:

Step 1: Add 20 g of PVA-1788 solution with a concentration of 10 wt %, 0.25 g of ethylene glycol, 2.5 g of PEDOT:PSS with a concentration of 1.0 wt % and 0.02 g of sodium polyacrylate into a 50 mL beaker. Disperse in the device for 5min, let stand for 12h to eliminate air bubbles, and obtain a homogeneous mixed solution;

Step 2: Cast the mixed solution obtained in Step 1 into a mold, freeze at -20°C for 20 hours, then thaw at 20°C for 4 hours, repeat the above freezing and thawing process 3 times, and then place in saturated sodium chloride solution Soak in 24h to obtain polyvinyl alcohol-based conductive hydrogel.

Wherein, PEDOT:PSS in embodiment 1-embodiment 6 is the PEDOT:PSS of commercially available commodity specification PH 1000; Described mould is made of polytetrafluoroethylene material groove body, and its inner groove size is the length, width, The depths are 100mm, 100mm, and 6mm respectively.

The tensile properties of the samples of Examples 1-6 were characterized by an Instron 5565 universal tensile machine, and the tensile rate was 30 mm/min;

The conductivity of the samples of Examples 1-6 was characterized by four-probe method (Keithley 2000);

The characterization results are shown in Table 1:

Table 1 Tensile properties and electrical conductivity of the polyvinyl alcohol-based conductive hydrogels prepared in Examples 1-6

As shown in Figure 1, the polyvinyl alcohol-based conductive hydrogel (strip shape, size 0.1cm×1cm×5cm) prepared in Example 3 was selected as the conductor, and it was tied to a finger, while the two The terminal is electrically connected to the positive and negative poles of the power supply (2V DC power supply), and the resistance value of the polyvinyl alcohol-based conductive hydrogel is measured in real time with the straightening or bending of the finger, as shown in Figure 1, every second The number of times of bending and straightening of the finger is about three times. When the finger is straightened, the resistance value is in the trough, and when the finger is fully bent, the resistance value is in the peak. Therefore, it can be considered that the resistance value of the polyvinyl alcohol-based conductive hydrogel will change with the deformation. The change can be applied to the flexible tension sensor.

The above is only the preferred embodiment of the present invention. It should be pointed out that for those of ordinary skill in the art, under the premise of not departing from the inventive concept of the present invention, some improvements and transformations can be made, which all belong to the protection of the present invention. scope.

Claims (3)

1. The preparation method of the polyvinyl alcohol-based conductive hydrogel is characterized by comprising the following steps:

step 1: adding 20g of 10 wt% PVA-1788 solution, 0.25g of ethylene glycol, 2.5g of 1.0 wt% PEDOT, PSS and 0.02g of sodium polyacrylate into a 50mL beaker, dispersing for 5min by a high-speed disperser at room temperature, and standing for 12h to eliminate bubbles to obtain a uniformly mixed solution;

step 2: casting the mixed solution obtained in the step 1 into a mold, freezing for 20 hours at-20 ℃, then unfreezing for 4 hours at 20 ℃, repeating the freezing and unfreezing process for 3 times, and then soaking in a saturated sodium chloride solution for 24 hours to obtain the polyvinyl alcohol-based conductive hydrogel;

the weight average molecular weight of the sodium polyacrylate is 300-700 ten thousand.

2. A polyvinyl alcohol-based electrically conductive hydrogel prepared by the method of preparing a polyvinyl alcohol-based electrically conductive hydrogel according to claim 1.

3. Use of the polyvinyl alcohol-based conductive hydrogel according to claim 2 in the preparation of artificial skin, flexible tension sensors or supercapacitors.

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