SYNTHESES AND CHROMOTROPISM OF SYNTHETIC SAPONITE-POLYMER NANOCOMPOSITES CONTAINING 3,3′,5,5′-TETRAMETHYLBENZIDINE

抄録

Chromotropism in clay-polymer nanocomposite consisted of synthetic saponite, poly-N-isopropylacrylamide (PNIPAAm), and 3,3′,5,5′-tetramethylbenzidine (TMB) was investigated by diffuse reflectance spectroscopy for dry powder specimens and UV-visible absorption spectroscopy for gel specimens. TMB was introduced in the photopolymerized saponite-PNIPAAm via a commonly used cation exchange method. The nanocomposites showed yellow color attributed to TMB radical in dry state but it turned to green by partial formation of blue charge-transfer complex in contacting to water, methanol, and acetonitrile vapor or liquid. The color change was particularly pronounced for acetonitrile and was evident even in a 10% aqueous solution for hydrogels.