高强高韧聚乙烯醇导电水凝胶的结构与传感性能

Structure and Sensing Property of Strong,Tough and Conductive Poly(Vinyl Alchol)Hydrogels

为了制备高强高韧导电水凝胶,采用能与聚乙烯醇(PVA)形成氢键相互作用的单宁酸(TA)为物理交联剂,以丙三醇和水为共溶剂制备得到具有纳米纤维网络结构的PVA/TA有机水凝胶;通过浸泡1 mol/L硝酸银溶液得到金属络合作用和氢键作用协同增强增韧的导电水凝胶。研究结果表明,当PVA和TA质量比为2:3时,水凝胶中TA与银离子能形成强烈的络合作用,进一步增强了TA与PVA分子链间形成的物理交联网络,凝胶内部形成了更为致密的网络结构,从而赋予导电水凝胶优异的力学性能,其强度、模量和韧性相较于未引入TA的PVA水凝胶分别提高了4.5倍、5倍和5倍。该导电水凝胶用于应变传感时,表现出优异的灵敏性(GF=99.4)、极高的线性度(R~2>0.99)和良好的循环稳定性(>500圈)。

The present study was performed aiming to prepare highly strong,tough and conductive hydrogels.Tannic acid(TA),which can form hydrogen bonding interactions with polyvinyl alcohol(PVA)molecular chains,was used as physical cross-linking agent to fabricate nanofibrillar PVA/TA organohydrogels via co-solvent method(glycerol and water co-solvent).The conductive hydrogels were prepared by soaking in 1 mol/L silver nitrate solution.When the mass ratio of PVA to TA is 2:3,the introduction of TA can form a strong complexation with silver ions,which can further enhance the physical cross-linking network with PVA molecular chains.The denser network structure inside the hydrogel endows the conductive hydrogel better mechanical properties.The strength,modulus and toughness of the hydrogel are increased by 4.5 times,5 times and 5 times respectively,compared with those of the hydrogel without TA.Furthermore,the conductive hydrogel exhibits high sensitivity(GF=99.4),high linearity(R~2>0.99)and good cycling stability(>500 cycles).