Noncovalent Method for Improving the Interaction between Reduced Graphene Oxide and Poly(ε-caprolactone)

Epitaxial crystallization of poly(e-caprolactone) (PCL) on reduced graphene oxide (RGO) was investigated by melt and solution crystallization. RGO and graphene oxide (GO) provided an opportunity to investigate the influence of surface functional groups on epitaxial crystallization with lattice matching. After annealing treatment, PCL/RGO composites showed an extra melting peak, which implied that epitaxial crystallization of PCL on RGO could form thicker lamellae. An analogous procedure of solution crystallization was used to confirm the epitaxy morphology and orientation of polymer chains. The results showed that PCL chains existed along the (2110) direction of the RGO (0001) plane forming edge-on lamellae, which implied strong interaction between PCL crystals and the RGO surface. Tensile test results showed that the yield strength and Young's modulus of PCL/RGO composites with epitaxial interaction were improved by about 34.2 and 53.2%, respectively, compared with neat PCL.