Nanoscale texture control of polyelectrolyte multilayer using spray layer-by-layer method

Weak polyelectrolyte multilayer thin films deposited by sequential spraying of poly(allylamine hydrochloride) (PAH) and poly(acrylic acid) (PAA) solutions are described. Using the spray layer-by-layer (spray-LBL) method, nanoscale texture structures were fabricated considering several factors such as the concentration of spray solution, spray quantity, and the flow rate of spray solution. It was also found that the formation of nanoscale texture structures was dependent on all three factors. Then, their surface morphologies were characterized. The surface morphologies of the fabricated films were observed by field-emission scanning electron microscopy (FE-SEM) and atomic force microscopy (AFM). The FESEM and AFM images showed that using the spray-LBL method, the surface morphology can be controlled with nanometer-order accuracy. As a result, the speed of fabricating thin films by the spray-LBL method was markedly increased compared with that by the dipping LBL method.