Dispersion of Functionalized Silver Nanoparticles in Polymer Matrices: Stability, Characterization, and Physical Properties

摘要

Three types of silver/polymer nanocomposite films were prepared: (1) silver/polymethyl methacrylate, (2) silver/ polystyrene, and (3) silver/polyt-butyl methacrylate by mixing colloidal solution of functionalized Ag nanoparticles with solution of pre-made polymers. The nanoparticles are randomly dispersed into the matrices. The desired surface functionality of Ag nanoparticle was achieved by using specific amphiphilic block copolymer (specific hydrophobic block part) as stabilizer. The stability of nanoparticles in these host hydrophobic polymer matrices was determined after annealing the nanocomposite films at high temperature. The nanoparticles remained stable and no agglomeration occurred upon annealing up to 120 ℃. Up to 20 wt% of block copolymer stabilized Ag nanoparticles (11% Ag) was successfully loaded in the polymer matrix. Such a dispersion of Ag nanoparticles into a hydrophobic polymer matrix significantly enhances the mechanical properties of the nanocomposite films. The storage and loss modulus increase with increasing Ag nanoparticles content. Compared with a polymer matrix, the polymer/Ag nanocomposites film (containing 0.65% of Ag) prepared by this method displayed storage modulus that are up to 130% higher. This is attributed to the high surface area of the polymer coated Ag nanoparticles in the polymer matrix and van der Waal's attraction force between surface of Ag nanoparticles (polymer brush) and host polymer matrix. Comparison of thermal properties of polymer and polymer/ Ag nanocomposite films showed that the thermal stability of nanocomposites increases by about 20 C.