Polymer composites filled with DNA-functionalized graphene nanoplatelets. Effects of DNA modification on the curing behavior and properties of PDMS-based matrices

In this paper, we report our recent results on the preparation and characterization of biocompatible nanocomposites made of a silicone-based polymer matrix with tunable elasticity (polydimethylsiloxane, PDMS, and its mixtures with hydroxyl-terminated PDMS) and DNA-functionalized graphene nanoplatelets as fillers. The aim is to exploit the biocompatible character and the high flexibility of the PDMS matrix, together with the exceptional mechanical strength, and good thermal and electrical conductivity of the graphene nanofillers (GNP) for applications in biomedical and sensing devices. Thermal analysis by differential scanning calorimetry (DSC) was conducted to study the curing process of the PDMS-based composites containing the DNA-functionalized graphene nanoplatelets. The properties of the final composites after cure were characterized using several techniques, including optical microscopy, surface wettability, and nanoindentation. We show that the elasticity of the polymer matrix can be varied by adding a less viscous component (PDMS-OH), whereas the electrical conductivity of the nanocomposite can be tuned by acting on the concentration and type of graphene-DNA assembly.