Polyelectrolyte complexes (PECs) have attracted considerable attention owing to their unique physicochemical properties and potential applications as smart materials. Herein, the glass transitions of PECs solvated with varying alcohols are investigated in poly(diallyldimethylammonium)/poly(acrylic acid) (PDADMA/PAA) complexes by using modulated differential scanning calorimetry (MDSC). Solvents with one or two hydroxyl groups are selected to examine the effect of PAA-solvent interactions on the glass transition temperature (T_g). Except for glycerol, all alcohol solvents yield PECs with detectable T_g’s and plasticization behavior. Furthermore, a linear relationship for 1/T_g and the natural logarithm of the number of hydroxyl groups to intrinsic ion pair ratio [ln(n_hydroxyl/n_{intrinsic-ion-pair})] is found. This result is significant because prior work demonstrated the relationship only for water and no other solvents. All-atom molecular dynamics (MD) simulations analyze the ability of the solvent to form hydrogen bonds via the solvent’s OH groups to the PAA, revealing that the solvent molecule size and available hydroxyl groups govern the change in the glass transition. Overall, the clear dependence of a PEC’s glass transition on the solvent’s chemical structure provides a simple guideline for predicting their relationship.

中文翻译：

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聚电解质配合物的溶剂响应玻璃化转变行为


聚电解质复合物 （PEC） 因其独特的物理化学性质和作为智能材料的潜在应用而受到广泛关注。本文使用调制差示扫描量热法 （MDSC） 研究了聚（二烯丙基二甲基铵）/聚（丙烯酸）（PDADMA/PAA）配合物中用不同醇溶剂化的 PECs 的玻璃化转变。选择具有一个或两个羟基的溶剂来检查 PAA-溶剂相互作用对玻璃化转变温度 （T_g） 的影响。除甘油外，所有醇溶剂都会产生具有可检测的 T_g 和塑化行为的 PEC。此外，发现了 1/T_g 和羟基数与本征离子对比 [ln（n_hydroxyl/n_{intrinsic-ion-pair}）] 的自然对数的线性关系。这一结果很重要，因为之前的工作证明了这种关系仅适用于水，而没有其他溶剂。全原子分子动力学 （MD） 模拟分析了溶剂通过溶剂的 OH 基团与 PAA 形成氢键的能力，揭示了溶剂分子大小和可用的羟基控制玻璃化转变的变化。总体而言，PEC 的玻璃化转变对溶剂化学结构的明显依赖性为预测它们之间的关系提供了一个简单的指南。