Different coating on electrospun nanofiber via layer-by-layer self-assembly for their photocatalytic activities

The water-stable PAA/PVA/PW 12 nanofiber was firstly prepared by electrospinning and thermal treatments. The negatively charged phosphotungstic acid (PW 12 ), positively charged polyethylenimine (PEI) and silver nanoparticle (Ag NPs) were alternatively deposited onto the fibrous substrate by layer-by-layer (LBL) self-assembly technique. The photocatalytic activity of different coated LBL film was observed under visible light irradiation. The results indicated that the conversion rate of methylene blue (MB) was gradually decreased with increasing the number of bilayers pairs. The behavior might ascribe to the more polycation electrolyte PEI that prevented from permeating for the MB molecule. On the other hand, in terms of the effects of surface charges on the photocatalytic activity, negatively charged surface (PEI) n (PW 12 ) n indicated higher photocatalytic activity than that of positively charged surface (PEI) n (PW 12 ) n − 1 . For the Ag NPs deposited on the LBL film, Ag-(PEI) n (PW 12 ) n film were found to be a better photocatalytic activity than other multilayer films, specially, Ag-(PEI) 2 (PW 12 ) 2 exhibited the most excellent activity due to the influence of the synergy in the hybrid materials.