PVA/AgNWs导电水凝胶微纤维的微流控制备及其性能研究

Microfluidic fabrication and properties of conductive PVA/AgNWs hydrogel microfibers

基于微流控技术产生的全水相喷射液流模板,由快速界面交联反应连续可控制备了含银纳米线(AgNWs)和锂离子的聚乙烯醇导电水凝胶微纤维(简称微纤维),对微纤维的结构与性能进行了研究。结果表明:以AgNWs质量浓度为10 g/L的内相流体制得的微纤维,其纤维截面呈三维多孔网络结构,且多孔网络结构中较均匀分布着AgNWs颗粒,该纤维的表面结构致密且均匀地分布着大量银元素,其含银的质量分数为17.65%;AgNWs的引入有效提高了微纤维的导电性能和力学性能,该微纤维电阻值最小达到392.28 kΩ;通过浸泡乙二醇/水溶液赋予了微纤维良好的抗冻能力和力学性能,降温至-60℃时微纤维内部的水溶液亦不会发生凝固,该微纤维的断裂伸长率、断裂强度和弹性模量由浸泡前的498.6%、1.67 kPa和1.9 MPa分别提高到浸泡后的633.7%、7.36 kPa和5.06 MPa;该微纤维可在较宽的应变范围(0~250%)内灵敏(灵敏度系数为2.02)、重复、稳定地响应外界拉伸作用,从而展现出相应的电阻变化;同时,该微纤维亦可灵敏重复地响应外界温度变化(0~60℃),而展现出灵敏、重复的电阻变化,显示出优良的应变/温度双重的传感功能。

Based on a whole water phase liquid jet flow template by the microfluidic technology,a conductive polyvinyl alcohol hydrogel microfiber(short for microfiber)containing silver nanowires(AgNWs)and lithium ion was prepared by continuously controlled fast interfacial crosslinking reaction.The structure and properties of the microfiber were studied.The results showed that the cross-section of the microfiber prepared by the inner phase fluid with a AgNWs concentration of 10 g/L was of a three-dimensional porous network structure evenly distributed with AgNWs particles when the surface structure of the microfiber was dense and evenly distributed with a large amount of silver at a mass fraction of 17.65%;the introduction of AgNWs effectively improved the electrical and mechanical properties of the microfiber,and the minimum resistance of the microfiber reached 392.28 kΩ;the microfibers acquired good freezing resistance and mechanical properties after soaking in glycol/water solution and the water solution inside the microfiber will not solidify even when the temperature reduced to-60℃,and the elongation at break,breaking strength and elastic modulus of the microfiber increased from 498.6%,1.67 kPa and 1.9 MPa to 633.7%,7.36 kPa and 5.06 MPa,respectively,after soaking;and the microfiber can sensitively(sensitivity coefficient was 2.02),repeatedly and stably respond to an external tension in a wide strain range(0-250%),thus showing corresponding resistance changes;meanwhile,the microfiber can also sensitively and repeatedly respond to the external temperature change(0-60℃)and show sensitive and repetitive resistance change,indicating excellent strain/temperature dual sensing function.