Abstract:
Optical sensor films were prepared by the layer-by-layer (lbl) self-assembly of polycationic (poly(diallydimethylammonium chloride) (PDADMAC) and metallic nanoparticle modified with water-soluble polyaniline (Ag-PANI) or PDADMAC and PANT The metallic nanoparticles were prepared by chemical reduction of silver nitrate by sodium borohydnde in the presence of various concentrations of water-soluble polyaniline. Three types of copolymers having different ratios of sulfonic to carboxylic acid groups were used in the interfacial polymerization of aniline to produce three kinds of water-soluble PANI used as capping agent of the silver nanoparticles. The optical and electrical properties of polyaniline and the silver nanoparticle solution as well as the thin film assembly were measured by ultra violet spectroscopy (UV). The three kinds of copolymers led to the formation of PANI, thus having different characteristics of water-soluble PANI to stabilize the silver nanoparticles in solution. The optical properties and conductivity of the films were sensitive to pH change when exposed to acidic and basic compounds. These films could be used as optical sensors for food quality.
