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

我们研究了气/水界面聚合物接枝亚微米颗粒单分子膜体系，发现由颗粒接枝的甲基丙烯酸酯聚合物在气/水界面有较大的伸展。在这里，我们用表面压力(π)-占据面积(A)等温线描述了聚合物接枝聚苯乙烯胶乳在空气/水和油/水界面形成颗粒层的行为。聚甲基丙烯酸甲酯接枝聚苯乙烯乳胶层和聚甲基丙烯酸丁酯接枝聚苯乙烯乳胶层在正庚烷/水界面的表面压力π比空气/水界面的表面压力在较大的占有率上增加了20%。此外，我们还根据π-A等温线估算了各界面处颗粒层的弹性模数。正庚烷/水界面颗粒层弹性模量值低于气/水界面颗粒层弹性模量值。在辛烷/水体系中，聚合物链在辛烷相比在空气中更容易移动，从而导致粒子单层的弹性模数较低。与PSL-PnBMA相比，PSL-PMMA颗粒单分子膜在空气/水和正十二烷/水界面的弹性模量值都较高，这表明PSL-PMMA形成的颗粒单分子膜比PSL-PnBMA形成更坚硬的颗粒单分子膜。

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.