A benign route for the production of polymer nanocomposite films based on poly(vinyl alcohol) and SiO2 nanoparticles modified with folic acid

The synthesis of high-performance polymer/inorganic nanocomposite (NCs) has attracted much attention. This idea comes from the combination of the advantageous properties of inorganic nanoparticles (NPs) and polymers. Nano-SiO2 particles are widely used as the inorganic component to prepare polymer/inorganic NCs. the high hydrophilicity originating from the hydroxyl group (−OH) on the silica surface and the high surface energy cause the NPs to easily agglomerate, therefore, it is difficult to disperse the nano-SiO2 in polymer matrix. Surface modification is the best method for uniform dispersion of NPs [1]. Poly(vinyl alcohol) (PVA) is a water-soluble polymer which has been studied as a host matrix for a large number of nano-fillers, due to its excellent properties. It is biodegradable, biocompatible and nontoxic [2]. In this paper to prevent the agglomeration of SiO2 NPs, their surface was modified by folic acid (FA) for the first time. Then, modified NPs was placed in the PVA matrix and SiO2-FA/PVA NC films with 2, 5, and 8 wt% were produced by casting method under ultrasonic radiation as a green and low-cost method. Transmission electron microscopy (TEM) showed that the size of SiO2-FA NPs in the PVA matrix was between 12-18 nm. Field emission scanning electron microscopy (FE-SEM) showed distribution of homogeneous particles in the PVA matrix.