Thermomechanical and Conductive Properties of Thiol-Ene Poly(ionic liquid) Networks Containing Backbone and Pendant lmidazolium Groups
Thermomechanical and Conductive Properties of Thiol-Ene Poly(ionic liquid) Networks Containing Backbone and Pendant lmidazolium Groups
复制标题
DOI：
10.1021/acs.iecr.8b04720
复制
发表时间：
2018-12-05
影响因子：
4.2
通讯作者：
Miller, Kevin M.
中科院分区：
文献类型：
--
作者：
Bratton, Abigail F.;Kim, Sung-Soo;Miller, Kevin M.
采用硫醇-烯“点击”光聚合法制备了一系列共价交联的聚(离子液体)网络。在这些网络中，咪唑基团被放置在主链的主干上，并悬挂在主链上，形成了一种“混合型”的网络结构。从含有可变长度的咪唑N-3位的末端烷基(R=C1、C4、C8、C12、C16或C20)或在新形成的硫化物和咪唑环之间含有可变的烷基链间隔基(n=6或10)的单官能单体将咪唑基结合到网络中。对这些网络的热表征表明，随着末端烷基链长从C1增加到C8，T-g普遍下降，随后由于较长链之间的van der Waals相互作用增加，T-g突然增加到C20。X射线散射数据证实了C16和C20体系的网络腔内存在扩链微晶，导致了观察到的T-g的增加和两个体系的熔融转变。在30℃、30%RH下，从介电弛豫谱(10(-6)~10(-7)S/cm)测定了PIL网络的离子电导，发现与聚合物的T-g有直接的相关性。
A series of covalently cross-linked poly(ionic liquid) networks were prepared using thiol-ene "click" photopolymerization. In these networks, imidazolium groups are placed in the backbone and pendant to the main chain, creating a "hybrid"-type network architecture. The pendant imidazolium groups were incorporated into the networks from monofunctional "ene" monomers that contained either a terminal alkyl group at the imidazolium N-3 position of variable length (R = C1, C4, C8, C12, C16, or C20) or a variable alkyl tether spacer (n = 6 or 10) between the newly formed sulfide and the imidazolium ring. Thermal characterization of these networks indicated a general decrease in T-g as the length of the terminal alkyl chain length increased from C1 to C8, followed by an abrupt increase in T-g up to C20 due to increased van der Waals interactions between longer chains. X-ray scattering data confirmed the presence of chain-extended crystallites within the network cavities for the C16 and C20 systems, leading to the observed increase in T-g and the appearance of a melting transition for both systems. Ionic conductivities of the PIL networks were determined from dielectric relaxation spectroscopy (10(-6) to 10(-7) S/cm at 30 degrees C, 30% RH), and a direct correlation with polymer T-g was found.