Direction and pressure response of osmotic pressure in binary polymer solutions

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• 作者：Junhan Cho
• 关键词：osmosis ; negative osmotic pressure ; equation of state ; pressure response
• 刊名：Macromolecular Research
• 出版年：2017
• 出版时间：January 2017
• 年：2017
• 卷：25
• 期：1
• 页码：79-84
• 全文大小：
• 刊物类别：Chemistry and Materials Science
• 刊物主题：Polymer Sciences; Soft and Granular Matter, Complex Fluids and Microfluidics; Physical Chemistry; Characterization and Evaluation of Materials; Nanochemistry; Nanotechnology;
• 出版者：The Polymer Society of Korea
• ISSN：2092-7673
• 卷排序：25

文摘

Using a molecular equation-of-state (EOS) theory, I discuss the direction and pressure response of osmotic pressure П for a composite system with a pure solvent and its non-ideal solution of a polymeric component separated by a semi-permeable membrane. A perturbed hard sphere chain model is chosen here for the EOS to estimate П in a general way while pressure is applied. It is shown that П is a phase behavior in connection with the phase stability of the solution. In case of an incompatible pair upon forcing a single phase, there exists a region inside the binodal line for negative П possessing a spinodal point as the threshold of П=0. It is the potential energy term that contributes to the negative П and drives solvent molecules away from polymers. Those actions are reversed when phase separation occurs on the solution side. In addition, it is revealed that the solution responds to pressure with either increase or decrease in П upon pressurization, which depends on the pressure coefficients of spinodals and solvent compressibility.