聚乙烯-乙烯酸) 双块共聚合物的囊泡膜上的质子扩散
1Department of Chemistry, McGill University, 801 Sherbrooke Street West, Montreal, Quebec, Canada H3A 2K6.
Journal of the American Chemical Society
|March 2, 2006
概括
通过使用pH梯度研究了跨块共聚合物膜的质子扩散. 添加二氧化使膜变质,增加了质子的透性,并作为一个封闭机制.
科学领域:
- 聚合物科学 聚合物科学
- 物理化学 物理化学
- 材料科学 材料科学 材料科学
背景情况:
- 块共聚合物囊泡自组装成具有可调节膜特性的结构.
- 聚乙烯-乙烯酸 (PS-b-PAA) 双块共聚合物形成适合研究运输现象的囊泡.
- 控制的pH梯度对于研究跨膜的质子扩散至关重要.
研究的目的:
- 为了研究通过聚乙烯-乙烯酸 (PS-b-PAA) 阻断共聚合物囊膜的质子扩散.
- 为了确定二氧化度对质子透性的影响.
- 探索膜塑化作为质子门机制的潜力.
主要方法:
- 在稀释水溶液中形成PS-b-PAA囊泡.
- 在囊泡膜上形成pH梯度 (pH在) ≈2.9,pH在) ≈8.5).
- 使用pH敏感的光染料 (8-hydroxypyrene-1,3,6-trisulfonate) 监测外部质子度.
- 将度-时间数据与扩散模型相匹配,以计算明显扩散系数 (D*).
主要成果:
- 质子度与时间的平方根线性增加.
- 质子增加的速度与二氧化含量正相关.
- 表面扩散系数 (D*) 范围从1.1×10−18厘米/秒 (7重%的二氧化) 到1.2×10−14厘米/秒 (40重%的二氧化).
结论:
- 二氧化可塑化了富含聚烯的膜,增强了质子扩散.
- 观察到的D*与二氧化度的增加表明了可调节的质子运输门机制.
- 块共聚合物囊泡为受控分子运输应用提供了一个有前途的平台.
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