阅读说明：本技术 一种具有高强度、高灵敏度的聚乙烯醇离子导电水凝胶制备方法 (Preparation method of polyvinyl alcohol ionic conductive hydrogel with high strength and high sensitivity ) 是由 孙平川 邸祥 伍国琳 于 2020-06-06 设计创作，主要内容包括：一种具有高强度、高灵敏度的聚乙烯醇离子导电水凝胶的制备方法,原料包括聚乙烯醇、NaCl等。制备包括以下步骤：1)不同结晶次数的PVA水凝胶的制备；2)PVA离子导电水凝胶的制备。本发明的优点在于：聚乙烯醇离子导电水凝胶含有大量氢键相互作用及盐析效应导致的高分子链链缠结,因此,具有可调控的高力学强度。体系中含水量高,离子的定向移动使其具有快速应变响应性及高灵敏度,可以实现运动监测及语音识别等应用。该凝胶制备方法简单,原料丰富,与传统的水凝胶相比,具有可调控的高力学强度、高灵敏度及可生物降解等性能,在组织工程、医用电极、柔性电子皮肤及智能传感器等领域有潜在的应用价值。(A process for preparing the high-strength and-sensitivity ionic-conducting polyvinyl alcohol hydrogel includes such steps as preparing polyvinyl alcohol and NaCl, and preparing the hydrogel. The preparation method comprises the following steps: 1) preparing PVA hydrogel with different crystallization times; 2) and (3) preparing PVA ionic conductive hydrogel. The invention has the advantages that: the polyvinyl alcohol ionic conductive hydrogel contains a large amount of high molecular chain entanglement caused by hydrogen bond interaction and salting-out effect, so that the polyvinyl alcohol ionic conductive hydrogel has controllable high mechanical strength. The water content in the system is high, and the directional movement of ions enables the system to have quick strain responsiveness and high sensitivity, and can realize applications such as motion monitoring and voice recognition. The gel is simple in preparation method and rich in raw materials, has adjustable and controllable performances such as high mechanical strength, high sensitivity and biodegradability compared with the traditional hydrogel, and has potential application values in the fields of tissue engineering, medical electrodes, flexible electronic skins, intelligent sensors and the like.)

1. A preparation method of polyvinyl alcohol ion conductive hydrogel with high strength and high sensitivity comprises the following steps:

step 1) preparation of PVA hydrogels with different crystallization times

Step 1.1) placing 3-20% of polyvinyl alcohol (PVA) in mass fraction in a container, adding deionized water, heating to 90-100 ℃, and violently stirring for 2-6 hours to completely dissolve the PVA;

step 1.2) standing the PVA solution for 5-20min, degassing by using a vacuum pump, removing bubbles in the solution, quickly transferring the solution into a mold, and standing until the solution is cooled to room temperature;

step 1.3) putting the mould into a refrigerator with the temperature of-20 ℃ for freezing for 2-6h, then putting the mould under the condition of room temperature, unfreezing for 6-12h, wherein the cycle times of freezing and unfreezing are 1-3 times, and obtaining PVA hydrogel with different crystallization times;

step 2) preparation of PVA ionic conduction hydrogel

Step 2.1) weighing excessive NaCl in a container, adding deionized water, and dissolving to obtain a saturated NaCl solution;

and 2.2) completely soaking the PVA hydrogel prepared in the step 1.3) in the NaCl solution obtained in the step 2.1), and controlling the soaking time to be 0.5-90min to obtain the PVA ionic conductive hydrogels with different strengths.

2. The method for preparing a high-strength and high-sensitivity polyvinyl alcohol ion-conducting hydrogel according to claim 1, wherein the method comprises the following steps: the molecular weight of the polyvinyl alcohol (PVA) is 146000-186000.

Technical Field

The invention belongs to the field of functional polymers and tissue engineering materials, and particularly relates to a preparation method and application of polyvinyl alcohol ion conductive hydrogel with high strength and high sensitivity.

Background

The hydrogel is a flexible material with a three-dimensional network structure, has high water content and good biocompatibility, is similar to human tissues, and is widely applied to tissue engineering, medical electrodes, wound repair, flexible electronic skin, intelligent sensors and the like. However, the traditional gel material free radical polymerization preparation process is complex, the synthesis conditions are harsh, the problems of poor mechanical property, slow response speed, low sensitivity and the like exist, and the application in the field of novel wearable devices cannot be met. Polyvinyl alcohol (PVA) hydrogel is a high molecular material with good biocompatibility and biodegradability, and can be used as an artificial cornea or a human articular cartilage material and the like.

Biological bodies mainly transmit electric signals by using ions, and gel materials based on an ion conduction mechanism are widely applied to flexible electronic and sensor materials.

The development of the hydrogel material with rapid, controllable, high strength and high sensitivity has wide application prospects in the fields of flexible electronic skin, intelligent sensors, motion monitoring, voice recognition and the like.

Disclosure of Invention

The invention aims to solve the problems of complex preparation process, harsh synthesis conditions, low and uncontrollable mechanical strength of materials, slow response speed and low sensitivity of the existing hydrogel, and provides a preparation method and application of polyvinyl alcohol ion-conductive hydrogel with high strength and high sensitivity.

The technical scheme of the invention is as follows:

a preparation method of polyvinyl alcohol ion conductive hydrogel with high strength and high sensitivity comprises the following steps:

step 1) preparation of PVA hydrogels with different crystallization times

Step 1.1) placing 3-20% of polyvinyl alcohol (PVA) in mass fraction into a container, adding deionized water, heating to 90-100 ℃, and violently stirring for 2-6 hours to completely dissolve the PVA.

Step 1.2) standing the PVA solution for 5-20min, degassing by using a vacuum pump, removing bubbles in the solution, quickly transferring the solution into a mold, and standing until the solution is cooled to room temperature.

And step 1.3) putting the mould into a refrigerator with the temperature of-20 ℃ for freezing for 2-6h, then placing the mould at room temperature for unfreezing for 6-12h, and controlling the cycle times of freezing and unfreezing to be 1-3 times to obtain the PVA hydrogel with different crystallization times.

Step 2) preparation of PVA ionic conduction hydrogel

And 2.1) weighing excessive NaCl in a container, adding deionized water, and dissolving to obtain a saturated NaCl solution.

And 2.2) completely soaking the PVA hydrogel prepared in the step 1.3) in the NaCl solution obtained in the step 2.1), and controlling the soaking time to be 0.5-90min to obtain the PVA ionic conductive hydrogels with different strengths.

The performance detection method of the prepared PVA ionic conduction hydrogel comprises the following steps:

1) detection of mechanical properties of PVA ion conductive hydrogel

The PVA ionic conduction hydrogel prepared by the method is cut into a standard dumbbell-shaped sample strip with the length of 3cm and the width of 5mm, and is stretched at the speed of 50mm/min by using an universal tensile machine (Shenzhen Sansi longitudinal and transverse science and technology Co., Ltd.), and the maximum load and the elongation at break are recorded. According to the formulaThe tensile strength was calculated, among others. The maximum load before breaking in the tensile test (unit: N), and S is the cross-sectional area of the gel (unit: mm)²). The strain was controlled to 50%, 100%, 200%, 300%, 400%, 500%, and the tensile rate was 50mm/min, and a cyclic loading-unloading test was performed. To ensure data accuracy, each set of samples was tested at least 3 times and the results averaged.

2) Strain-responsiveness detection of PVA ionically conductive hydrogels

The method comprises the steps of soaking 10% of PVA hydrogel with the thickness of 1mm in a saturated sodium chloride aqueous solution, controlling the soaking time, quickly preparing a high-toughness hydrogel sensor, fixing the hydrogel on a high-precision stepping motor, respectively controlling the small strain to be 0.2%, 0.4%, 0.8% and 1%, controlling the stretching rate to be 50mm/min, controlling the large strain to be 25%, 50% and 100%, controlling the stretching rate to be 200mm/min, combining the PVA hydrogel with a digital source meter with the model of GiTIMELI 2400, and recording the change of resistance along with deformation in real time.

3) Detection of different body part movements of PVA ionically conductive hydrogels

The prepared PVA ionic conductive hydrogel is cut into different lengths and is respectively fixed on each part of a body, including the parts of fingers, wrists, elbow joints, knee joints and the like, two ends of the prepared PVA ionic conductive hydrogel are respectively connected to a digital source meter with the model of Jishili 2400 through leads and are connected with a computer, and the resistance change of the hydrogel is monitored in real time. Each action was repeated at least 5 times.

4) PVA ionic conduction hydrogel language identification detection

The prepared PVA ionic conductive hydrogel is cut into 3 multiplied by 0.8 multiplied by 0.5cm, is fixed at the position of vocal cord vibration, emits different sounds, records the resistance change caused by the vocal cord vibration in real time, records the sounds emitted by different testers, distinguishes the change of tone and the difference of different country voices, and repeats at least 5 times each action.

The invention has the advantages and beneficial effects that:

the method of the invention prepares polyvinyl alcohol hydrogel with different mass fractions and different crystallization times, and obtains PVA ionic conduction hydrogel with different strengths by changing the soaking time in NaCl saturated solution. A large amount of hydrogen bond interaction and salting-out effect in the PVA ionic conduction hydrogel cause tight chain entanglement of a high molecular chain, so that the hydrogel has good mechanical strength and excellent biocompatibility. The PVA ionic conduction hydrogel prepared by the method fully exerts the synergistic interaction of a PVA high molecular chain and NaCl, realizes the quick and effective control of the mechanical property of the hydrogel by controlling the circulating freeze-thaw times and the soaking time, has good ionic conductivity and strain responsiveness, and can realize quick response, high-sensitivity motion monitoring, voice recognition and the like.

The PVA ionic conductive hydrogel prepared by the method has high strength and high sensitivity, can play an important role in the fields of flexible electronic skin, language identification and wearable electronic equipment, and has wide application prospect.

Drawings

FIG. 1 is a diagram illustrating the mechanical property detection of PVA ionic conduction hydrogel. Wherein, a is the tensile stress-strain curve of the PVA gel in the embodiment 3 in different soaking times, and b is the cyclic tensile curve of the PVA ionic conduction hydrogel in the embodiment 3 in different strains.

FIG. 2 is a measurement of the strain responsiveness of the PVA ionically conductive hydrogel of example 3. Wherein a is a relative resistance change curve of the PVA ionic conduction hydrogel under small strain, and b is a relative resistance change curve of the PVA ionic conduction hydrogel under large strain.

FIG. 3 shows the detection of the movement of different body parts of the PVA ionically conductive hydrogel according to example 3. Wherein a is a relative resistance change curve of the PVA ionic conductive hydrogel when a finger is bent by 30 degrees, 60 degrees and 90 degrees, and b-d are relative change curves of real-time resistance when a wrist, an elbow and a knee are bent respectively.

FIG. 4 is a speech recognition test of the PVA ionically conductive hydrogel of example 3. Wherein, a and b are relative resistance change curves recorded by the PVA ionic conductive hydrogel in Chinese "Nihao" and English "Hello", respectively, and c and d are relative resistance change curves recorded by the PVA ionic conductive hydrogel in "Thankyou" of male and female testers.

Detailed Description