A theoretical investigation on the pH-induced switching of mixed polyelectrolyte brushes

作者：Zhao Xin jun^*; Zhang Guo liang

来源：Chinese Journal of Polymer Science, 2014, 32(5): 568-576.

DOI：10.1007/s10118-014-1429-6

• Mixed polyelectrolyte brushes
• Molecular theory
• pH-induced switching

A theoretical investigation on the pH-induced switching of mixed polyelectrolyte brushes was performed by using a molecular theory. The results indicate that the switching properties of mixed polyelectrolyte brushes are dependent on the pH values. At low pH, negatively charged chains adopt a compact conformation on the bottom of the brush while positively charged chains are highly stretched away from the surface. At high pH values, the inverse transformation takes place. The role of pH determining the polymer chains conformation and charge behavior of mixed polyelectrolyte brushes was analyzed. It is found that there exists a mechanism for reducing strong electrostatic repulsions: stretching of the chains. The H+ and OH- units play a more important role as counterions of the charged polymers do. The collapse of the polyelectrolyte chains for different pH values could be attributed to the screening of the electrostatic interactions and the counterion-mediated attractive interaction along the chains.

• 出版日期2014-5
• 单位伊犁师范大学