Low density polyethylene coated by graphene nanoplatelets

An advantageous micromechanical technique to deposit large area graphene nanoplatelet (GNP) thin films on a low-density polyethylene substrate is proposed. This method, based on the application of shear-stress and friction forces to a graphite platelets/ethanol paste on the surface of a polymeric substrate, allows to obtain films of overlapped nanoplatelets mainly made of 13-30 graphene layers. X-ray diffraction (XRD), atomic force and transmission electron microscopy (TEM) measurements support the occurrence of a partial exfoliation of the graphite platelets due to shear-stress and friction forces applied during film formation. Scanning electron microscopy (SEM) observations point out that the surface of the polymer is uniformly coated by GNP unities, and the TEM analysis reveals the tendency of the nanoplatelets to align parallel to the interfacial plane. It has been found that the deposited samples, under white light illumination, exhibit a negative photoconductivity and a linear photoresponse as a function of the applied voltage and the optical power density in the -120÷120 mV and 20.9÷286.2 mWcm-2 ranges, respectively. These structural and electrical characteristics will be compared to those of LDPE films coated with thin layers deposited by spraying a commercial graphite-based product.