Tailoring the Thermal Diffusivity of Polyvinylidene Fluoride via Carbon Source Integration: A Photothermal Beam Deflection Study

Abstract

The work reported in the paper addresses the thermal diffusivity (TD) tuning of the electronic sensor material polyvinylidene fluoride (PVDF). The thermal properties of electronic material were found to influence the device characteristics significantly, demanding novel techniques for TD tuning. The TD value of the carbon sources—hydroxyethyl cellulose (HC), lignin (LG), and camphor soot (CS) and their composites—were measured by the sensitive nondestructive evaluation technique—photothermal beam deflection. When the HC and LG enhanced the TD of PVDF by 237.5% and 27.5%, respectively, CS was found to lower it by 11.25%. The spectroscopic analysis revealed the variation of hydroxyl groups in the samples and suggested its prominence in deciding the TD value. The Fourier transform infrared analysis and beam deflection measurements exhibited a positive correlation between hydroxyl groups and TD, except for the composite PVDF combined with soot. In this case, the amorphous carbon in soot reduced PVDF’s TD due to the heat trap mechanism of carbon allotropes. The induced variation of TD of PVDF via carbon source integration is attributed to the closure of pores in PVDF, revealed through the optical microscopic images, thereby suggesting a methodology for enhancing or reducing TD of PVDF.