pH-sensitive characteristics of poly(acrylic acid)-functionalized anodic aluminum oxide (AAO) membranes

• Published in: Journal of membrane science 2011-04, Vol.372 (1), p.340-345
• Main Authors: Song, Cunfeng, Shi, Wei, Jiang, Hairong, Tu, Jing, Ge, Dongtao
• Format: Article
• Language: English
• Subjects: AAO membrane; acrylic acid; aluminum oxide; artificial membranes; Chemistry; Colloidal gels. Colloidal sols; Colloidal state and disperse state; dielectric spectroscopy; Electrochemistry; electrolytes; Exact sciences and technology; General and physical chemistry; Membranes; Permeability; pH-sensitive; polyacrylic acid; Pore-filled membranes; Porous materials; Silica; sol-gel processing
• ISSN: 0376-7388; 1873-3123
• DOI: 10.1016/j.memsci.2011.02.017

[Display omitted] ► A novel pH-responsive membrane was prepared using aluminum oxide membrane as matrix. ► The membrane exhibited reversible response of the flux to the environmental pH. ► The pH-valve effect was observed at the pH between 3 and 5. ► Membrane resistance increased from 4.3 × 10 5 Ω cm 2 at pH 2 to 1.3 × 10 6 Ω cm 2 at pH 6. A simplified method to prepare pore-filled pH-responsive membranes was provided by using anodic aluminum oxide (AAO) membrane as supported matrix. To introduce reactive groups for grafting weak polyelectrolyte, silica–AAO composite membrane was prepared by depositing silica onto the AAO membrane through sol–gel method. The obtained composite membrane keeps the ideal pore structures of the original AAO membrane. Poly(acrylic acid) as responsive polymer was grafted onto the silica–AAO composite membranes by activating with 3-glycidoxypropyl trimethoxysilane. The obtained pH-responsive membranes showed evident pH-sensitivity, and the pH-valve effect was observed at the pH between 3 and 5. Electrochemical impedance spectroscopy demonstrates the membrane resistance increases from 4.3 × 10 5 Ω cm 2 at pH 2 to 1.3 × 10 6 Ω cm 2 at pH 6.