Deposition of nano-scaled zinc oxide on polyelectrolyte film by layer-by-layer technique

Abstract

Deposition of nano-scaled ZnO particles on polyelectrolyte film was conducted by 3 different methods which are precipitation of ZnO, suspension of ZnO in poly(acylic acid) (PAA) and sol-gel methods. Based on the experimental results, a suitable condition for preparation of polyelectrolyte film was dipping glass substrate into 2.0 M polyelectrolyte solution (poly(allylamine hydrochloride) and poly(acrylic acid) with a withdrawal speed at 3 cm/min. Deposition of ZnO particles onto a single bilayer polyelectrolyte film could be achieved by the sol-gel method with pH of sol precursor at 1. The incorporated polyelectrolyte film with ZnO exhibits transmittance of 95% in visible light range and highly hydrophilic property with the water contact angle of lower than 5 degrees after UV irradiation for 15 min. The method of suspension of ZnO in poly(acrylic acid) (PAA) could also provide polyelectrolyte film containing ZnO which improve hydrophilic property of the coated substrates. However, activation UV with longer time compared with that of the sol-gel method would be required. This result is attributed to the agglomeration of ZnO in the polymer solution before coating, leading to lower hydrophilic property.