Amine enrichment of thin-film composite membranes via low pressure plasma polymerization for antimicrobial adhesion

Rackel Reis, Ludovic Dumee, Li He, Fenghua She, John D. Orbell, Bjorn Winther-Jensen, Mikel Collin Duke

Research output: Contribution to journalArticleResearchpeer-review

24 Citations (Scopus)

Abstract

Thin-film composite membranes, primarily based on poly(amide) (PA) semipermeable materials, are nowadays the dominant technology used in pressure driven water desalination systems. Despite offering superior water permeation and salt selectivity, their surface properties, such as their charge and roughness, cannot be extensively tuned due to the intrinsic fabrication process of the membranes by interfacial polymerization. The alteration of these properties would lead to a better control of the materials surface zeta potential, which is critical to finely tune selectivity and enhance the membrane materials stability when exposed to complex industrial waste streams. Low pressure plasma was employed to introduce amine functionalities onto the PA surface of commercially available thin-film composite (TFC) membranes. Morphological changes after plasma polymerization were analyzed by SEM and AFM, and average surface roughness decreased by 29%. Amine enrichment provided isoelectric point changes from pH 3.7 to 5.2 for 5 to 15 min of plasma polymerization time. Synchrotron FTIR mappings of the amine-modified surface indicated the addition of a discrete 60 nm film to the PA layer. Furthermore, metal affinity was confirmed by the enhanced binding of silver to the modified surface, supported by an increased antimicrobial functionality with demonstrable elimination of E. coli growth. Essential salt rejection was shown minimally compromised for faster polymerization processes. Plasma polymerization is therefore a viable route to producing functional amine enriched thinfilm composite PA membrane surfaces.
Original languageEnglish
Pages (from-to)14644 - 14653
Number of pages10
JournalACS Applied Materials & Interfaces
Volume7
Issue number27
DOIs
Publication statusPublished - 2015

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