Photo-regulated conductivity of polycaprolactone honeycomb-patterned porous films containing azobenzene-functionalized reduced graphene oxide

Photo-regulated electrical conductive materials plays an important role in light driven applications such as photo-switching, reversible optical storage etc. Designing of such materials in flexible porous polymeric forms adds advantage in terms of light weight, less density, enhanced performance due to increased surface area. As a result we have synthesized poly(epsilon-caprolactone) (PCL) composite via in situ ring opening polymerization of epsilon-caprolactone in the presence of azobenzene-functionalized reduced graphene oxide (rGO-Azo) and studied its photo-regulated conductive properties in porous and flat films. PCL-rGO-Azo composites were characterized using Fourier transform infrared and UV-vis spectroscopy. Honeycombpatterned porous films were fabricated by breath figure method. The morphology of the films was examined by scanning electron microscopy (SEM). Photo-regulated conductivity of the PCL-rGO-Azo films depending on the UV and visible light illumination has been studied. The conductivity was increased by UV irradiation and recovered by visible light irradiation. The conductivity change is due to the trans-cis isomerization of azobenzene moieties covalent-bonded to reduced graphene oxide (rGO).