title: Hydrophilic modification of PVDF microfiltration membranes by adsorption of facial amphiphile cholic acid.
abstract: Amphiphilic molecules have been widely used in surface modification of polymeric materials. Bile acids are natural biological compounds and possess special facial amphiphilic structure with a unusual distribution of hydrophobic and hydrophilic regions. Based on the facial amphiphilicity, cholic acid (CA), one of the bile acids, was utilized for the hydrophilic modification of poly(vinylidene fluoride) (PVDF) microfiltration membranes via the hydrophobic interactions between the hydrophobic face of CA and the membrane surfaces. Ethanol, methanol, and water were respectively used as solvent during CA adsorption procedure. Their polarity affects the CA adsorption amount, as similar to CA concentration and adsorption time. There are no changes on the membrane surface morphology after CA adsorption. The hydrophilicity of PVDF membranes is greatly enhanced and the water drops permeates into the CA modified membranes quickly after modification. All these factors benefit to the permeation flux of membrane for water. When CA concentration is higher than 0.088 M, the water permeation flux is doubled as compared with the nascent PVDF membrane and shows a good stability during filtration procedure. These results reveal the promising potential of facial amphiphilic bile acids for the surface modification of polymeric materials.
authors.affiliation: Department of Applied Chemistry, School of Food Science and Biotechnology, Zhejiang Gongshang University, Hangzhou 310018, China. Electronic address: mengxinhu@zjgsu.edu.cn.
authors.forename: Meng-Xin
authors.initials: MX
authors.lastname: Hu
authors.affiliation: Department of Applied Chemistry, School of Food Science and Biotechnology, Zhejiang Gongshang University, Hangzhou 310018, China.
authors.forename: Ji-Nian
authors.initials: JN
authors.lastname: Li
authors.affiliation: Key Laboratory of Macromolecular Synthesis and Functionalization, Department of Polymer Science & Engineering, Zhejiang University, Hangzhou 310027, China.
authors.forename: Shi-Lin
authors.initials: SL
authors.lastname: Zhang
authors.affiliation: Department of Applied Chemistry, School of Food Science and Biotechnology, Zhejiang Gongshang University, Hangzhou 310018, China.
authors.forename: Liang
authors.initials: L
authors.lastname: Li
authors.affiliation: Key Laboratory of Macromolecular Synthesis and Functionalization, Department of Polymer Science & Engineering, Zhejiang University, Hangzhou 310027, China.
authors.forename: Zhi-Kang
authors.initials: ZK
authors.lastname: Xu
mesh_terms: D019826:Cholic Acid / Q000737:chemistry*; D005374:Filtration / Q000379:methods*; D057927:Hydrophobic and Hydrophilic Interactions; D011145:Polyvinyls / Q000737:chemistry*; D013499:Surface Properties; D005465:Fluorocarbon Polymers
chemical_list: D019826:Cholic Acid; D011145:Polyvinyls; C024865:polyvinylidene fluoride; D005465:Fluorocarbon Polymers
keywords: Adsorption; Cholic acid; Facial amphiphile; Hydrophilicity; PVDF microfiltration membrane