Dielectric study on membrane adsorption and release:Relaxation mechanism and diffusion dynamics

• 来源期刊: 中国科学B辑(英文版)
• 年，卷（期）: 2008,（9）
• 页码范围: 813-822
• 页数: 10页
• 语种: 英文
• DOI: 10.1007/s11426-008-0037-0

摘要

Dielectric monitoring of the adsorption or release process of salicylic acid (SA) by chitosan membrane shows that the dielectric spectra of the chitosan membrane/SA solution systems change regularly in the adsorption or release process. By analyzing the regularity, a new mechanism for the relaxations is proposed. The concentration polarization layer (CPL) caused by SA adsorption or release is confirmed to be essential for the dielectric relaxations. The changes of the spectra with time are explained by account of the relationship between CPL properties and dielectric strength. Based on this relaxation mechanism, a theoretical method can be established to calculate dynamical parameters of inner structure of the adsorption or release systems from their dielectric spectra. Therefore, dielectric spec-troscopy is demonstrated to be a promising method for estimating interfacial distribution of ionic sub-stances and their binding to membrane in a non-invasive way.