Structural Estimation and Dynamics of Polymer-grafted Particle at Soft Interfaces

我们研究了聚合物接枝亚微米粒子在空气/水界面上的单分子层体系，发现由粒子接枝的甲基丙烯酸酯聚合物在空气/水界面上有相当大的延伸。本文通过表面压力（π）-占有面积（A）等温线研究了聚合物接枝聚苯乙烯胶乳在空气/水和油/水界面上的颗粒层形成行为。聚甲基丙烯酸甲酯接枝聚苯乙烯胶乳（PSL-PMMA）和聚甲基丙烯酸正丁酯接枝聚苯乙烯胶乳（PSL-PnBMA）在癸烷/水界面上的表面压力π在较大的占有面积处开始增加，比空气/水界面增加20%。此外，我们估计的颗粒层的弹性模量从π-A等温线在每个界面。颗粒层在癸烷/水界面处的弹性模量比在空气/水界面处的弹性模量低。高分子链在辛烷相中比在空气中更容易运动，这是辛烷/水体系中颗粒单层弹性模量较低的原因。PSL-PMMA粒子单层膜在空气/水和癸烷/水界面上的弹性模量均高于PSL-PnBMA，说明PSL-PMMA粒子单层膜比PSL-PnBMA粒子单层膜更硬。

We have studied polymer-grafted submicron particle monolayer system at the air/water interface, and we have found that methacrylate polymers grafted from particle are fairly extended at the air/water interface. Here, we present the behaviors of polymer-grafted polystyrene latex in particle layer formation at the air/water and oil/water interfaces by surface pressure (π)-occupied area (A) isotherms. Surface pressure, π, of poly(methyl methacrylate)-grafted polystyrene latex (PSL-PMMA) layer and poly(n-butyl methacrylate)-grafted polystyrene latex (PSL-PnBMA) at decane/water interface began to increase surface pressure at larger occupied area compared with those at the air/water interface by 20%. Furthermore, we estimated elastic modulus of particle layer from π-A isotherms at each interface. Elastic modulus of particle layer at decane/water interface showed lower values compared with those at the air/water interface. Polymer chain move more easily in the octane phase than in the air, which contributes the lower elastic modulas in particle monolayer at octane/water system. PSL-PMMA particle monolayer showed higher values of elastic modulas compared with those of PSL-PnBMA at either air/water and decane/water interfaces, which suggested PSL-PMMA formed harder particle monolayer than PSL-PnBMA.