Instrumented indentation of PMMA/ZnO nanocomposites films

Abstract Piezoelectric nanocomposite films comprise zinc oxide (ZnO) nanoparticles as reinforcement and poly-methyl methacrylate (PMMA) as the matrix. These films can potentially be used as structural and functional components of microdevices that can harvest energy from ambient mechanical vibrations. The design of such energy-scavenging micro/nano-systems will require knowledge of the process-microstructure-property relationships of nanocomposite films. This study synthesized PMMA/ZnO nanocomposite films using ultrasonic probe sonication and solution-casting. The nanomechanical characterization of the nanocomposite films was conducted using a nanoindenter via quasi-static mode. Quasi-static nanoindentation revealed that the indentation modulus ranged from 3.49 ± 0.03 GPa for PMMA to 4.71 ± 0.07 GPa for PMMA/ZnO 5 wt% nanocomposite film. However, the indentation modulus of 10 wt% ZnO nanocomposites decreases, i.e. 4.22 ± 0.60 GPa. The indentation hardness varied from 311.97 ± 6 MPa for PMMA thermoplastic polymer to 432.94 ± 83.81 MPa for PMMA/ZnO 10 wt% nanocomposites film. In addition, the properties of the nanocomposite film vary, as supported by scanning electron micrographs.