Surface Modification of Polyethersulfone Hollow Fiber Membrane for Water Recovery Using Layer-by-Layer Nanocoating Method

Polyethersulfone (PBS) hollow fiber membrane was surface-modified for application as a separation membrane to recover water vapor from the flue gas. Hydrophilic sulfonated PES (SPES) was prepared by introducing a sulfonic acid group in PES structure and was used for the layer-by-layer (LbL) coating solution with polyallyamine hydrochloride (PAR). The surface characteristics of the modified PES membranes were observed by XPS, SEM, zeta-potential and contact angle measurements. The formation of hydrophilic nano-coating layer with 50 similar to 80 nm in thickness on the surface of PBS hollow fiber membranes by the LbL coating method led to relatively lower contact angle and higher water vapor permeance. As a result, the LbL coating method could be considered as a useful method for surface-modification of PBS hollow fiber membrane to enhance their surface hydrophilicity and water vapor permeance.