Production and evaluation of the surface properties of chiral poly(amide-imide)/TiO2 nanocomposites containing L-phenylalanine units

This study concerted on the immobilization of nano-titanium dioxide particles (TiO2, 30-50 nm particle size) into or onto an optically active poly(amide-imide) (PAI). The matrix PAI consisted of the chiral units in the main and hydroxybenzamide functional groups in the side chains. The macromolecule structure has been fabricated from the reaction of 3,5-diamino-N-(4-hydroxyphenyl) benzamide and N,N'-(pyromellitoyl)-bis-L-phenylalanine diacid chloride at low temperature. The hydroxyl groups on the side chains of the PAI could provide better compatibility and bonding, which cause to suitable homogenous dispersion of nanoparticles (NPs) in the obtained nanocomposites (NCs). Also due to prevention of aggregation, the surface of TiO2 NPs was functionalized by 3-aminopropyltri-ethoxysilane as a coupling agent to introduce amine groups on the NPs surfaces. Atomic force microscopy, field emission scanning electron microscopy, transmission electron microscopy and contact angle measurements were used for investigation of the surface properties of obtained NCs. These results confirmed the well-dispersion of nanoTiO(2) in the PAI matrix. (C) 2012 Elsevier B.V. All rights reserved.