Critical Role of Ion Exchange Conditions on the Properties of Network Ionic Polymers.
Critical Role of Ion Exchange Conditions on the Properties of Network Ionic Polymers.
复制标题
离子交换条件对网络离子聚合物性能的关键作用。
DOI：
10.1021/acsmacrolett.0c00678.s001
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发表时间：
2020
影响因子：
7.015
通讯作者：
C. M. Evans
中科院分区：
文献类型：
--
作者：
Naisong Shan;Chengtian Shen;C. M. Evans
离子聚合物在广泛的应用中是重要的，并且可以根据离子种类表现出广泛不同的性质。在单离子导电聚合物的情况下，其中一个电荷连接到主链或作为侧基，进行离子交换以控制移动的物质。虽然条件经常被指定，但最终的离子含量并不总是量化的，并且对于交换中需要什么浓度的盐没有明确的标准。合成了一系列在离子结之间具有不同精确碳间隔基（C4-C7）的铵网络离子聚合物作为模型系统，以了解离子交换条件如何影响所得聚合物性质。用1.5、3或10当量的双（三氟甲烷）磺酰亚胺锂（LiTFSI）盐在溶液中交换具有游离溴阴离子的初始网络。对于在交联之间具有七个碳的网络，增加LiTFSI浓度导致离子交换效率从83.6摩尔%增加到97.6摩尔%。在最高转化率下，C7网络显示玻璃化转变温度（Tg）降低4 °C，降解温度增加50 °C，从空气中的吸水率降低12倍，并且在90 °C下电导率增加大于10倍。这些结果表明，诸如Tg的性质对残留离子杂质不太敏感，而电导率高度依赖于最终的交换转化率。
Ionic polymers are important in a wide range of applications and can exhibit widely different properties depending on the ionic species. In the case of single ion conducting polymers, where one charge is attached to the backbone or as a side group, ion exchange is performed to control the mobile species. While the conditions are often specified, the final ion content is not always quantified, and there are no clear criteria for what concentration of salt is needed in the exchange. A series of ammonium network ionic polymers with different precise carbon spacers (C4-C7) between ionic junctions were synthesized as model systems to understand how the ion exchange conditions impact the resultant polymer properties. The initial networks with free bromide anions were exchanged with 1.5, 3, or 10 equiv of lithium bis(trifluoromethane)sulfonimide (LiTFSI) salt in solution. For networks with seven carbons between cross-links, increasing the LiTFSI concentration led to an increase in ion exchange efficiency from 83.6 to 97.6 mol %. At the highest conversion, the C7 network showed a 4 °C decrease in glass transition temperature (Tg), a 50 °C increase in degradation temperature, 12-fold lower water uptake from air, and a greater than 10-fold increase in conductivity at 90 °C. These results illustrate that properties such as Tg are less sensitive to residual ion impurities, whereas the conductivity is highly dependent on the final exchange conversion.
影响因子：
5.5
作者：
Ford, Hunter O.;Merrill, Laura C.;Schaefer, Jennifer L.
通讯作者：
Schaefer, Jennifer L.
影响因子：
4.2
作者：
Bratton, Abigail F.;Kim, Sung-Soo;Miller, Kevin M.
通讯作者：
Miller, Kevin M.
影响因子：
4
作者：
Elmore, Clay T.;Seidler, Morgan E.;Schaefer, Jennifer L.
通讯作者：
Schaefer, Jennifer L.