The conductivity of polydimethylsiloxane/graphene nano-ribbon foam composite with elongation. (June 2020) - Jun, Yun-Seok
Abstract: This study demonstrates that the use of high aspect ratio graphene nano-ribbon (GNR) significantly improves electrical conductivity and retains higher electrical conductivity under strain. GNR was utilized to construct a three-dimensional foam via freeze casting. Poly (dimethylsiloxane) (PDMS) was subsequently infiltrated into the GNR foam to fabricate a PDMS composite (GNR-PDMS). As-prepared GNR-PDMS was compared with composites produced with reduced graphene oxide with small-sized diameter (rSGO-PDMS) and large-sized diameter (rLGO-PDMS). GNR-PDMS (1.2 wt%) shows conductivity of 1.0 × 10 −2 S/cm and only experiences 33% drop at 20% elongation. In contrast, rLGO-PDMS (0.6 wt%) and rSGO-PDMS (2.2 wt%) exhibit lower conductivity of 0.70 × 10 −2 S/cm and 0.27 × 10 −2 S/cm, respectively. At 20% elongation, rLGO-PDMS and rSGO-PDMS suffer from significant conductivity drop of 71% and 87%, respectively. The very good electrical sustainability of GNR-PDMS is due to the fact that individual GNR strips are piled up to create GNR-accumulated sheets that provide large contact areas in the percolated network, maintaining a high conductivity on stretching. Moreover, highly entangled and accumulated GNR sheets prevent encapsulation of individual strips, leading to improved electrical conductivity. Graphical abstract: Image 1