Surface modification of reverse osmosis desalination membranes by thin-film coatings deposited by initiated chemical vapor deposition

• Published in: Thin solid films 2013-07, Vol.539, p.181-187
• Main Authors: Ozaydin-Ince, Gozde, Matin, Asif, Khan, Zafarullah, Zaidi, S.M. Javaid, Gleason, Karen K.
• Format: Article
• Language: English
• Subjects: Biofouling; Chemical vapor deposition (including plasma-enhanced cvd, mocvd, etc.); Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Exact sciences and technology; Initiated chemical vapor deposition; Materials science; Mechanical and acoustical properties; Methods of deposition of films and coatings; film growth and epitaxy; Physical properties of thin films, nonelectronic; Physics; Polymer coatings; Reverse osmosis membranes; Structure and morphology; thickness; Surface modification; Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties); Thin film structure and morphology
• ISSN: 0040-6090; 1879-2731
• DOI: 10.1016/j.tsf.2013.04.133

Thin-film polymeric reverse osmosis membranes, due to their high permeation rates and good salt rejection capabilities, are widely used for seawater desalination. However, these membranes are prone to biofouling, which affects their performance and efficiency. In this work, we report a method to modify the membrane surface without damaging the active layer or significantly affecting the performance of the membrane. Amphiphilic copolymer films of hydrophilic hydroxyethylmethacrylate and hydrophobic perfluorodecylacrylate (PFA) were synthesized and deposited on commercial RO membranes using an initiated chemical vapor deposition technique which is a polymer deposition technique that involves free-radical polymerization initiated by gas-phase radicals. Relevant surface characteristics such as hydrophilicity and roughness could be systematically controlled by varying the polymer chemistry. Increasing the hydrophobic PFA content in the films leads to an increase in the surface roughness and hydrophobicity. Furthermore, the surface morphology studies performed using the atomic force microscopy show that as the thickness of the coating increases average surface roughness increases. Using this knowledge, the coating thickness and chemistry were optimized to achieve high permeate flux and to reduce cell attachment. Results of the static bacterial adhesion tests show that the attachment of bacterial cells is significantly reduced on the coated membranes. •Thin films are deposited on reverse osmosis membranes.•Amphiphilic thin films are resistant to protein attachment.•The permeation performance of the membranes is not affected by the coating.•The thin film coatings delayed the biofouling.