Interfacial Tension of Polyelectrolyte Complex Coacervate Phases

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• 作者：Jian Qin ; Dimitrios Priftis ; Robert Farina ; Sarah L. Perry ; Lorraine Leon ; Jonathan Whitmer ; Kyle Hoffmann ; Matthew Tirrell ; Juan J. de Pablo
• 刊名：ACS Macro Letters
• 出版年：2014
• 出版时间：June 17, 2014
• 年：2014
• 卷：3
• 期：6
• 页码：565-568
• 全文大小：255K
• 年卷期：v.3,no.6(June 17, 2014)
• ISSN：2161-1653

文摘

We consider polyelectrolyte solutions which, under suitable conditions, phase separate into a liquid-like coacervate phase and a coexisting supernatant phase that exhibit an extremely low interfacial tension. Such interfacial tension provides the basis for most coacervate-based applications, but little is known about it, including its dependence on molecular weight, charge density, and salt concentration. By combining a Debye鈥揌眉ckel treatment for electrostatic interactions with the Cahn鈥揌illiard theory, we derive explicit expressions for this interfacial tension. In the absence of added salts, we find that the interfacial tension scales as N^鈥?/2(畏/畏_c鈥?)^3/2 near the critical point of the demixing transition, and that it scales as 畏^1/2 far away from it, where N is the chain length and 畏 measures the electrostatic interaction strength as a function of temperature, dielectric constant, and charge density of the polyelectrolytes. For the case with added salts, we find that the interfacial tension scales with the salt concentration 蠄 as N^鈥?/4(1鈭捪?蠄_c)^3/2 near the critical salt concentration 蠄_c. Our predictions are shown to be in quantitative agreement with experiments and provide a means to design new materials based on polyelectrolyte complexation.