Influence of counteranion and humidity on the thermal, mechanical and conductive properties of covalently crosslinked ionenes
Influence of counteranion and humidity on the thermal, mechanical and conductive properties of covalently crosslinked ionenes
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DOI：
10.1016/j.polymer.2021.123641
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发表时间：
2021-04
期刊：
影响因子：
4.6
通讯作者：
Nicholas C Bontrager;S. Radomski;Samantha P. Daymon;R. Johnson;K. Miller
中科院分区：
文献类型：
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作者：
Nicholas C Bontrager;S. Radomski;Samantha P. Daymon;R. Johnson;K. Miller
采用硫醇-烯光聚合的方法合成了一系列共价交联的含咪唑的离子烯网络。选择了不同的反阴离子，以考察尺寸和碱度对所得网络的热、机械和导电性能的影响。在20℃时的无水电导率为10−6~10−10s/cm，与Tg有一定的相关性，但热重归一化曲线表明聚合物结构与电导率之间的关系更为复杂。为了提供更多的洞察力，研究了VFT拟合以及自由离子浓度和离子迁移率数据。这项研究的另一个有趣之处是湿度对离子电导率的影响。当相对湿度增加到70%时，含有[Cl]、[NO3]或[Oms]等阴离子的亲水网络的离子电导率有3~5个数量级的提高(最高可达10−3s/cm)，而疏水网络([Pf6]和[NTf2])不受影响。进一步的实验(吸水率，DSC)表明，观察到的导电性增强可能是由于塑化和水辅助离子传输的组合。
Thiol-ene photopolymerization was used to generate a series of covalently crosslinked, imidazolium-containing ionene networks. A variety of counteranions were chosen so as to investigate the influence of size and basicity on the thermal, mechanical and conductive properties of the resulting networks. Anhydrous conductivities at 20 °C were found to be on the order of 10−6to 10−10S/cm and correlated to some degree withTg; however,Tg-normalization of the curves indicated that this relationship between polymer structure and conductivity was more complex. VFT fitting, along with free ion concentration and ion mobility data, were investigated in order to provide additional insight. Also of interest in this study was the influence of humidity on ionic conductivity. Hydrophilic networks with anions such as [Cl], [NO3] or [OMs] were found to exhibit 3- to 5-orders of magnitude enhancement in ionic conductivity (up to 10−3S/cm) when the relative humidity was increased to 70% while the more hydrophobic networks ([PF6] and [NTf2]) were not influenced. Further experimentation (water uptake, DSC) indicated that the observed enhancements in conductivity were likely due to a combination of plasticization and water-assisted ion transport.