Synthesis of conductive polyaniline-carbon nanofiber nanocomposite with chenille like morphology for photocatalytic coatings applications

Abstract

Pristine carbon nanofibers (CNF) have been dispersed with a non-ionic surfactant, Triton X-100 and then acid oxidized (in H2SO4: HNO3, acid ratio 3:1). This ensures a consistent dispersion with attachments of water soluble functional groups (−COOH and OSO3H). Subsequently polyaniline (PANICNF) based nanocomposites, were prepared at low temperature (0–5) ˚C via in-situ polymerization approach. Triton X-100 facilitates the dispersion of bundled CNF, thereby assisting PANI molecules to uniformly coat the edge and surface sites of CNF. This gives rise to a unique core-shell structure with chenille like appearance (PANI@CNF), implying emeraldine PANICNF nanocomposite forms an interpenetrating network. A bandgap of∼1.37 eV as compared to PANI (3.17 eV) calculated using UV–vis Tauc plot curve fit shows that this unique morphology proves to be a boon for the photocatalytic coating formulation. Spectroscopic study also show that the obtained quinoid to benzenoid ring peak ratio for PANI is 1:0.992 and for PANI/CNF is 1:0.996 which is almost equal to one and is thus highly conductive. CNF prompts enhanced polaron movement from valence to conduction band in PANI/CNF while also acting as the acceptor layer to the quinoid rings in PANI which is the donor layer. A linear ohmic graph for PANI/CNF coatings was obtained using I–V (current-voltage) characteristic curves. Thus PANI/CNF nanocomposite coatings possessing a unique fuzzy fabric (chenille) like core-shell morphology has a tunable band gap, enhanced surface area and improved charge transfer properties and are potentially active photovoltaic coatings for environmentally exposed surfaces.