Thermal diffusivity measurements in PANI and PANI-MWNT composites using photo acoustic technique

Abstract

Hydrochloric acid (HCl) doped Polyaniline (PANI) and Polyaniline-Multiwalled Carbon Nano Tube (MWNT) composite samples were synthesized using chemical oxidative polymerization technique. Transmission Electron Microscopy (TEM) and Raman spectroscopy studies clearly establish the formation of PANI (HCl) and PANI (HCl)-MWNT composites. Thermal diffusivity measurements were carried out using Open Photo Acoustic Cell (OPC) technique in transmission configuration and the thermal diffusivity values were calculated. The thermal diffusivity of the composite samples is found to be greater than that of pure PANI. It increases with increase in MWNT loading upto aniline to MWNT feed ratio 1:0.3 and later decreases for the 1:0.5 sample. Still the thermal diffusivity of PANI (HCl)-MWNT composite sample is higher than that of PANI (HCl).The enhancement in thermal diffusivity is due to the high thermal conductivity of MWNT. The decrease in thermal diffusivity of the 1:0.5 sample is explained using dopant induced phonon scattering and thermal interfacial contact resistance. The present study offers ample scope for tailoring the thermal diffusivity parameters of polyaniline composites according to device requirements.