Compatibilizing hydrophilic and hydrophobic polymersviaspray coating for desalination

Junquan Meng, Cher Hon Lau*, Yunlong Xue, Rui Zhang, Bing Cao, Pei Li

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract / Description of output

The incompatibility between hydrophobic polymers such as polytetrafluoroethylene (PTFE) and hydrophilic polymers such as polyvinyl alcohol (PVA) is typically overcome by reducing the large surface energy difference between these materialsviacomplex protocols or using bespoke chemicals. In this study, we deployed the simple technique of spray coating to solve this incompatibility, depositing polyvinyl alcohol (PVA) onto PTFE porous support layers. This was achieved as sub-micron sized PVA solution droplets infiltrated and filled up PTFE inter-fiber pores, forming a tightly bound PVA layer on PTFE fibrous supports. The defect-free thin hydrophilic PVA layer and the porous hydrophobic PTFE substrate of the composites were exploited for desalination in both direct contact membrane distillation (DCMD) and pervaporation (PV) modes. When deployed to separate 3.5 wt% NaCl from water at 75.0 ± 0.9 °C with a permeate side pressure of 100 Pa in PV mode, these thin film composites demonstrated ultra-high water fluxes of 143.4 ± 8.9 kg m-2h-1, outperforming state-of-the-art PV membranes. Moreover, when the membrane was tested in DCMD mode with a cooling stream at 20.6 ± 0.3 °C, a water flux of 64.2 ± 2.9 kg m-2h-1was obtained and was on par with the best DCMD membranes. With excellent organic and ionic fouling resistances, these thin film composites can be potentially deployed to treat polluted brine mixtures, even under harsh operating conditions.

Original languageEnglish
Pages (from-to)8462-8468
Number of pages7
JournalJournal of Materials Chemistry A
Volume8
Issue number17
Early online date3 Apr 2020
DOIs
Publication statusPublished - 7 May 2020

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