Improved electrical and mechanical properties of highly stretchable polymeric films prepared by blending DMF with the mixed solution of PEDOT:PSS and PVA

Abstract

Stretchable conducting films of polymeric composite are prepared by mixing poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) with poly(vinyl alcohol) (PVA) in presence of polar organic solvent N,N-dimethylformamide (DMF) and their structural, morphological, and improved electrical and mechanical responses are investigated. In presence of DMF, X-ray diffraction pattern exhibits the shifting of the crystalline peak of PEDOT:PSS/PVA film towards higher diffraction angle and 10 wt% DMF blended film shows highest crystallinity of 52.9%. DMF transforms PEDOT conformation from benzoid to quinoid structure. FTIR and UV–vis spectroscopy confirm the formation of hydrogen bonds among PSS, PVA and DMF components, whereas AFM images show the increase in surface roughness with DMF concentration. The composite films exhibit non-linear current (I) - voltage (V) characteristics which follow the Poole-Frenkel charge transport mechanism. 10 wt% DMF blended film exhibits highest electrical response (nearly 7 times higher at 5 V). At higher DMF concentration, films become highly stretchable and 10 wt% DMF film has elongation at break around 333.0 ± 17% which is almost 2 times higher. With increasing number of loading-unloading cycle, irreversible damage occurs in the film. The optimum concentration of DMF in this polymeric composite is highly effective for its use as a stretchable conducting film.