阅读说明：本技术 一种具有透气导电水凝胶的制备方法 (Preparation method of breathable conductive hydrogel ) 是由 毕恒昌 刘星池 吴幸 蔡春华 王超伦 于 2021-08-06 设计创作，主要内容包括：本发明公开了一种具有透气导电水凝胶的制备方法,其特点是以水性石墨烯作为导电物质,DMSO为促进导电物质分散的溶剂与PVA、PVP交联,在加热搅拌下获得了可成胶的液体,然后使用微针模板,使成胶液体在冷凝过程中形成了多孔结构,制得具有透气导电水凝胶。本发明与现有技术相比具透气效果较好,制备工艺简单,易操作,清洁环保,成本低廉,适应性广,并可通过选择不同直径的微针也可以控制透气孔的直径,从而控制其透气性。(The invention discloses a preparation method of breathable conductive hydrogel, which is characterized in that aqueous graphene is used as a conductive substance, DMSO is used as a solvent for promoting the dispersion of the conductive substance to be crosslinked with PVA and PVP, a gel-forming liquid is obtained under heating and stirring, and then a microneedle template is used to ensure that the gel-forming liquid forms a porous structure in a condensation process, so that the breathable conductive hydrogel is prepared. Compared with the prior art, the invention has the advantages of better ventilation effect, simple preparation process, easy operation, cleanness, environmental protection, low cost and wide adaptability, and can control the diameter of the ventilation hole by selecting the microneedles with different diameters, thereby controlling the ventilation property.)

1. A preparation method of breathable conductive hydrogel is characterized in that a microneedle template method is adopted, a conductive gel solution forms a porous structure in a condensation process, and the preparation method of the breathable hydrogel specifically comprises the following steps:

a. adding water-based graphene into a mixed solution of deionized water and dimethyl sulfoxide, and performing ultrasonic dispersion for 1-2 hours to obtain a water-based graphene dispersion solution, wherein the mass ratio of the water-based graphene to the deionized water to the dimethyl sulfoxide is 3: 50-150: 100-300 parts;

b. adding PVA and PVP into the aqueous graphene dispersion liquid, and stirring at the temperature of 70-110 ℃ until the PVA and the PVP are melted and crosslinked, wherein the mass ratio of the PVA to the PVP to the aqueous graphene dispersion liquid is as follows: 8-10: 1: 80-100, wherein the stirring time is 1.5-13 h;

c. pouring a proper amount of the crosslinked gel solution into a flat-bottomed container, placing the needle point of a microneedle template downwards at the bottom of the container, condensing at the temperature of minus 70 to minus 20 ℃ for 1 to 3 hours, then melting at room temperature, repeating freeze thawing for at least 3 times, and taking out the microneedle template to prepare the breathable conductive hydrogel with the porous structure.

2. The method for preparing the hydrogel with gas-permeable and electrically conductive functions as claimed in claim 1, wherein the hydrogel prepared in step c is soaked in deionized water for 8 hours to remove dimethyl sulfoxide from the gel.

3. The method for preparing the hydrogel having gas permeability and conductivity according to claim 1, wherein the gas permeability of the hydrogel can be controlled by the diameter of the microneedle and the number of freeze-thaw cycles.

Technical Field

The invention relates to the technical field of preparation of conductive breathable hydrogel, in particular to a preparation method of conductive hydrogel with good breathability.

Background

In recent years, flexible electronics has become a further hot topic in the electronics field. Among them, the flexible and wearable sensor becomes a hot spot among hot spots. Among many flexible materials, hydrogels are very suitable for fabricating wearable sensors due to their good biocompatibility and low young's modulus. Hydrogel-based wearable sensors are also emerging in abundance, and to date, PAAm-based hydrogel sensors have been synthesized (Nano Energy,2019,58: 96-104); sensors based on PVA hydrogels (Advanced Materials Technologies,2018,3: 1802576), and sodium alginate composite hydrogels (Nanoscale, 2015,7: 14766-.

The hydrogel in the prior art has no air permeability, so that the wearable sensor manufactured by the hydrogel is poor in wearing comfort when being attached to the surface of skin for a long time. Therefore, there is a need to find a widely applicable method for providing hydrogel with certain breathability for wearing for a long time, thereby improving the wearing experience.

Disclosure of Invention

The invention aims to provide a preparation method of a breathable conductive hydrogel, which is designed aiming at the defects of the prior art, the method of a microneedle template is adopted, a conductive gel solution forms a porous structure in the condensation process, the prepared hydrogel has good breathability and conductivity, the gel is used for a flexible strain sensor attached to the surface of the skin for a long time, the experience degree is further improved, the wearing comfort is good, the breathability of the finished gel product can be controlled by selecting microneedles with different diameters, the diameter of the pores of the gel is controllable, the preparation process is simple, the operation is easy, the production cost is low, the preparation method is widely suitable for hydrogels with various components, the breathability effect is good, and the application prospect is good.

The purpose of the invention is realized as follows: a preparation method of breathable conductive hydrogel is characterized in that a microneedle template is adopted to prepare porous breathable hydrogel, and the preparation method specifically comprises the following steps:

a. ultrasonically dispersing water-based graphene in a mixed system of deionized water and dimethyl sulfoxide (DMSO) to obtain a water-based graphene dispersion liquid, wherein the mass ratio of the water-based graphene to the deionized water to the DMSO is 3: 50-150: 100-300 parts; the ultrasonic dispersion time is 1-2 h.

b. Adding PVA and PVP into the uniformly dispersed aqueous graphene dispersion liquid, and stirring at the temperature of 70-110 ℃ until the PVA and the PVP are completely dissolved and crosslinked, wherein the mass ratio of the PVA to the PVP to the aqueous graphene dispersion liquid is as follows: 8-10: 1: 80-100 parts.

c. Pouring a proper amount of the cross-linked gel solution into a flat-bottomed container, placing the needle point of a microneedle template downwards at the bottom of the container, namely placing the microneedle downwards into the solution, freezing at a low temperature, then melting at room temperature, repeatedly freezing and thawing for at least 3 times, and taking out the microneedle to prepare the breathable hydrogel with a porous structure (small holes for ventilation in the prepared gel can be observed), wherein the low-temperature freezing is carried out for condensation for 1-3 hours at the temperature of-70 to-20 ℃.

d. And (3) soaking the prepared gel in deionized water for more than 8 hours at room temperature to leach the DMSO added in the preparation process.

The ultrasonic dispersion time is preferably more than 1 h.

The PVA is preferably AR, 1799 type.

The PVP is preferably K30, having a molecular weight of 40000.

The cross-linking stirring time is preferably 2-3 h, and the stirring temperature is preferably 80-100 ℃.

Compared with the prior art, the invention has the advantages of good air permeability and electric conductivity, good air permeability effect, low cost, cleanness, environmental protection, simple preparation process, cleanness, environmental protection and low cost, is widely suitable for the preparation of gel of various conductive substances or networks, has wide adaptability, and can control the diameter of the air vent by selecting the micro-needles with different diameters so as to control the air permeability.

Drawings

FIG. 1 is a schematic flow chart of the operation of the present invention;

FIG. 2 is a gas-permeable hydrogel prepared in example 1.

Detailed Description

Referring to the attached figure 1, the method for preparing the breathable conductive hydrogel from the breathable conductive hydrogel specifically comprises the following steps of:

a. adding a conductive substance (aqueous graphene) into a mixed solution of deionized water and dimethyl sulfoxide, and performing ultrasonic dispersion.

b. Adding PVA and PVP into the dispersed system, and continuously stirring at about 90 ℃ until the PVA and the PVP are completely dissolved and crosslinked.

c. And (3) transferring a proper amount of the dispersed liquid into a flat-bottom container, placing the micro-needle into the liquid to be used as a template for forming the air vent, condensing for a plurality of hours at low temperature, thawing at room temperature after freezing, and taking down the micro-needle after freezing and thawing for a plurality of times to obtain the air-permeable hydrogel.

d. The prepared hydrogel is placed in deionized water for soaking at room temperature, and DMSO added in the preparation process can be leached out.

The invention is further illustrated below by way of example for the preparation of electrically conductive gels of different air permeability.

Example 1:

1) and (3) putting 21g of deionized water, 11g of dimethyl sulfoxide and 0.29g of aqueous graphene into a clean and dry container, and placing the container in an ultrasonic cleaner for ultrasonic dispersion for 1 hour to observe that the graphene is uniformly dispersed in the solution.

2) 6.3g of PVA and 0.7g of PVA are added into the dispersed solution, heated to 70 ℃ on a magnetic stirring table and magnetically stirred for 1.5h until the PVA and the PVP are completely dissolved and crosslinked.

3) Placing a proper amount of the crosslinked solution in a clean and dry flat-bottom container, placing the array needle point of the microneedle template on the liquid level in a downward manner, and placing the microneedle template in a freeze dryer to freeze for 1.5 hours at the temperature of-40 ℃.

4) And taking out the frozen micro-needle template, thawing the frozen micro-needle template at room temperature, repeatedly freezing and thawing the frozen micro-needle template for three times, and taking out the micro-needle template to obtain the breathable hydrogel.

5) And (3) soaking the breathable hydrogel in deionized water for one night, and taking out the breathable hydrogel the next day to prepare the breathable conductive hydrogel with the graphene content of 0.4%.

Referring to FIG. 2, the hydrogel having a porous structure prepared in the above example has a certain air permeability.

Example 2

1) And (3) putting 21g of deionized water, 21g of dimethyl sulfoxide and 0.45g of aqueous graphene into a clean and dry container, and placing the container in an ultrasonic cleaner for ultrasonic dispersion for 1.5h, so that the graphene can be observed to be uniformly dispersed in the solution.

2) 6.3g of PVA and 0.7g of PVA are added into the solution, the solution is heated to 85 ℃ on a magnetic stirring table and is magnetically stirred for 2 hours until the PVA and the PVP are completely dissolved and crosslinked.

3) Placing a proper amount of the crosslinked solution in a clean and dry flat-bottom container, placing the array needle point of the microneedle template on the liquid level in a downward manner, and placing the microneedle template in a freeze dryer to freeze for 2 hours at the temperature of-50 ℃.

4) And taking out the frozen micro-needle template, thawing the frozen micro-needle template at room temperature, repeatedly freezing and thawing the frozen micro-needle template for three times, and taking out the micro-needle template to obtain the breathable hydrogel.

5) And (3) soaking the breathable hydrogel in deionized water overnight, and taking out the breathable hydrogel the next day to obtain the breathable conductive hydrogel with the graphene content of 0.6%.

Referring to FIG. 2, the hydrogel having a porous structure prepared in the above example has good air permeability.

Example 3:

1) taking 21g of deionized water, 42g of dimethyl sulfoxide and 0.60g of aqueous graphene, putting the deionized water, the dimethyl sulfoxide and the aqueous graphene into a clean and dry container, and placing the container in an ultrasonic cleaner for ultrasonic dispersion for 2 hours, so that the graphene can be observed to be uniformly dispersed in the solution.

2) 6g of PVA and 1.0g of PVA are added into the solution, the solution is heated to 110 ℃ on a magnetic stirring table and is magnetically stirred for 3 hours until the PVA and the PVP are completely dissolved and crosslinked.

3) Placing a proper amount of the crosslinked solution in a clean and dry flat-bottom container, placing the array needle point of the microneedle template on the liquid level in a downward manner, and placing the microneedle template in a freeze dryer to freeze for 3 hours at the temperature of-60 ℃.

4) And taking out the frozen micro-needle template, thawing the frozen micro-needle template at room temperature, repeatedly freezing and thawing the frozen micro-needle template for three times, and taking out the micro-needle template to obtain the breathable hydrogel.

5) And (3) soaking the breathable hydrogel in deionized water for 20h, and taking out the breathable hydrogel the next day to obtain the breathable conductive hydrogel with the graphene content of 0.8%.

Referring to FIG. 2, the hydrogel having a porous structure prepared in the above example has good air permeability.

The diameter of the air holes can be controlled by selecting the micro-needles with different diameters, so that the air permeability of the micro-needles can be controlled. While the invention has been described with reference to a preferred embodiment, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.