Automatic Spray-LBL Machine Based on in-Situ QCM Monitoring

Aqueous-based spray-layer-by-layer (spray-LBL) techniques have become an innovative, economic, and fast fabrication process, particularly in comparison to conventional LBL, dipping techniques. The spray-LBL method has enhanced the growth of polyelectrolyte multilayer films using spray pressure. In this study, we have fabricated an automatic spray-LEL machine and have monitored the real-time growth of multilayer films using quartz crystal microbalance (QCM) techniques. We have discussed the process of multilayer thin film growth and the effect of spray pressure on film growth. We have fabricated polyelectrolyte multilayer films on gold, using poly(allylamine hydrochloride) (PAH) as the polycation and poly(acrylic acid) (PAA) as the polyanion. UV-vis spectroscopic data showed that visible light transmission was similar to that of bare slide glass. Fabrication using the automatic spray-LBL machine and real-time QCM monitoring allows the fabrication of optical quality thin films with precise thickness.