Effects of GnF Concentration on the Mechanoelectrical Properties and Surface Morphology of GnF/PDMS Composites

Abstract

The graphite nanoflake (GnF)-reinforced polydimethylsiloxane (PDMS) composites (GnF/PDMS composites) are developed as new polymer matrix composites (PMCs) with controllable mechanoelectrical properties. Here, we investigate the effect of GnF concentration on the mechanoelectrical properties (i.e., elastic modulus, fracture strain, and conductivity) of GnF/PDMS composites; the change in the surface morphology of GnF/PDMS composites caused by a variation in GnF concentration is also explored. The mechanoelectrical properties are measured by performing tensile tests on the GnF/PDMS composite specimens with different GnF concentrations of 5.0, 10.0, 12.5, 15.0, 20.0, and 25.0 wt.%. The surface morphology is analyzed in terms of internal void formation and surface roughness. The elastic modulus is measured to be in the range of 1.62 to 13.8 MPa which is proportional to GnF concentration, while the fracture strain and electrical conductivity are respectively characterized to be in ranges of 0.09 to 2.09 and 0.3 to 221.0 S/m which are in inverse proportion to GnF concentration. An increase in GnF concentration leads to increases in internal voids’ amount and surface roughness. The GnF/PDMS composites can be used as sensing materials for detecting both small and large deformations in a variety of engineering applications.