聚酸结构和聚化分子量对多层膜内横向扩散的影响
Jordan Brito1, Parin Purvin Shah1, Aliaksei Aliakseyeu2
1Department of Materials Science & Engineering, Texas A&M University, College Station, Texas 77840, USA.
The Journal of chemical physics
|March 26, 2024
概括
了解多电解质多层动态是应用的关键. 这项研究揭示了星形聚甲酸在多层中表现出比线性链更高的流动性,扩散受到合作伙伴聚酸的影响.
科学领域:
- 材料科学 材料科学 材料科学
- 聚合物化学 聚合物化学
- 物理化学 物理化学
背景情况:
- 多电解质多层 (PEMs) 具有多种应用,但其动态特性仍然不太清楚.
- 了解PEM中的聚合物扩散对于优化其性能至关重要.
研究的目的:
- 为了研究薄弱的多酸 (多甲酸,PMAA) 在层对层 (LbL) 组件中的线性和8臂架构的质量中心扩散.
- 确定聚化 (poly ((diallyldimethylammonium) ,PDADMAC) 分子重量和PMAA结构对膜生长和聚合物动态的影响.
主要方法:
- 使用PMAA (线性和8臂) 和PDADMAC制造LbL PEM.
- 在不同的盐和pH条件下对薄膜沉积的分析.
- 在光标记PMAA (PMAA*) 上使用光漂白后光恢复 (FRAP) 测量侧面聚合物扩散.
主要成果:
- 薄膜沉积在低盐,酸性条件下产生更厚,更分散的层,具有更短的PDADMAC链.
- 双层厚度随着PDADMAC分子量增加而降低;PMAA架构对薄膜生长有很小的影响.
- 暴露于0.2M NaCl降低了PMAA的电离,并诱导了显著的横向扩散率 (D = 10−13 到 10−12 cm2/s).
- 八臂PMAA显示出比线性PMAA更高的聚合物流动性.
- 扩散系数对PDADMAC分子重量的依赖性很弱 (n < 0.6),但8臂PMAA扩散受到多基化分子连接性的更强烈影响.
结论:
- 聚合物架构 (线性与8臂) 影响PEM内部的聚合物流动性,恒星聚合物表现出增强的扩散.
- 反聚合物的分子量和连接性在调节多层结构内的多电解质扩散方面发挥着作用.
- 这些发现为PEM的动态行为提供了关键的见解,为高级应用程序的设计提供了信息.
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