A molecular dynamics study of the mechanical and electrical properties of Polydimethylsiloxane-Ni conductive nanocomposites

Molecular dynamics was applied to develop a novel PDMS and PDMS-Ni nanocomposite model. First, the PDMS model was validated in terms of the elastic and compressive moduli using available experimental data. The model was then used as a benchmark to add Ni nanoparticles and create a PDMS-Ni conductive nanocomposite model. This model was studied under uniaxial tensile and compressive loading conditions for different Ni filler ratios and mean particle diameters. The electrical resistivity of the model was then obtained as a function of pressure and the compressive stresses. The PDMS-Ni MD model was validated via the literature and shown to successfully predict electrical resistivity variations versus compressive stresses. The results show that as the Ni filler ratio increased from 3:1 to 6:1, the drop in initial electrical resistivity of the composites occurred much faster and at lower stresses. Furthermore, as the mean Ni particle diameter size was increased from 1 nm to 5 nm, the electrical conductivity of the PDMS-Ni improved at different filler ratios. The developed PDMS-Ni MD model can be used to study the electrical and mechanical behaviors of such materials in biosensor applications. It can further be used to study the effects of adding other fillers to PDMS matrix.