Department of Chemistry, University of Oregon, Eugene, Oregon 97403, USA.
Langmuir. 2013 Sep 3;29(35):10980-9. doi: 10.1021/la4021096. Epub 2013 Aug 22.
Large macromolecules with hydrophobic backbones are known to assemble at the interface between immiscible liquids. This assembly is often unpredictable because of the subtle interplay among hydrophobic interactions, hydrophilic solvation, structural constraints, and the thermodynamics of adsorption. In these studies, we employ vibrational sum frequency spectroscopy and interfacial tension measurements to study the assembly of a simple polyelectrolyte, poly(methacrylic acid), as it assembles at the interface between two immiscible liquids, specifically, carbon tetrachloride and water. By adjusting the polyelectrolyte charge through pH studies and the polymer size through molecular weight studies, we demonstrate that charge accumulation in segments of the polymer chains is a critical factor in macromolecular interfacial adsorption and desorption. The results have implications for related charged macromolecules whose ability to assemble between two immiscible fluid media is essential for many biological processes, water remediation efforts, and enhanced oil recovery.
已知具有疏水骨架的大分子会在不混溶液体的界面处组装。由于疏水相互作用、亲水性溶剂化、结构约束和吸附热力学之间的微妙相互作用，这种组装通常是不可预测的。在这些研究中，我们采用振动和频光谱和界面张力测量来研究一种简单的聚电解质，聚（甲基丙烯酸），当它在两种不混溶液体（即四氯化碳和水）之间的界面上组装时的组装情况。通过通过 pH 值研究调整聚电解质的电荷和通过分子量研究调整聚合物的大小，我们证明聚合物链段中的电荷积累是大分子界面吸附和脱附的关键因素。这些结果对相关的带电大分子具有启示意义，它们在两种不混溶流体介质之间组装的能力对许多生物过程、水修复努力和提高石油采收率至关重要。
