Sedimentation of Polyelectrolyte Chains in Aqueous Solutions

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• 作者：Zhenli Luo ; Guangzhao Zhang
• 刊名：Macromolecules
• 出版年：2010
• 出版时间：December 14, 2010
• 年：2010
• 卷：43
• 期：23
• 页码：10038-10044
• 全文大小：831K
• 年卷期：v.43,no.23(December 14, 2010)
• ISSN：1520-5835

文摘

We have investigated the dynamics of poly(sodium styrenesulfonate) (PSSNa) in aqueous solutions with and without added salt (NaCl) by use of analytical ultracentrifuge (AUC) via sedimentation velocity (SV) as a function of NaCl concentration (C_s) or PSSNa concentration (C_p). As C_s increases, the sedimentation coefficient monotonically increases, whereas the diffusion coefficient shows a minimum. On the other hand, as C_p increases, the sedimentation coefficient decreases while the diffusion coefficient exhibits a minimum at C_s < 1.0 × 10⁻³ M. However, they linearly vary with C_p at C_s > 1.0 × 10⁻³ M. The scaling relation between the molar mass and sedimentation coefficient or diffusion coefficient at infinite dilution indicates that PSSNa chain changes from an extended conformation to a random coil as NaCl concentration increases. Our experiments demonstrate that the dynamics of polyelectrolyte chains is mediated by interchain electrostatic repulsion, hydrodynamic interactions, and intrinsic excluded volume effect.