M. S. THESIS COLLOQUIUM
Name: Ms. Devanshi Gupta
Title: Investigation of Dielectric and Humidity Sensing Behaviour of Graphite and Functionalised Graphene doped Polyvinylidene fluoride (PVDF) Composites
Date &Time : Thursday, 6th June 2024 at 4.00 p.m.
Venue: Rajarshi Bhattacharya Memorial Lecture Hall, Chemical Sciences Building
Abstract:
The present research work explores the dielectric and humidity sensing behaviour of graphite and functionalised graphene doped polyvinylidene fluoride (PVDF) composites. For the study, the films of PVDF-based composite films were prepared using the solvent casting method. Filler materials like graphite (procured), graphene oxide prepared from improved Hummer’s method, and reduced graphene oxide prepared using the hydrothermal method were used. Structural, functional, and morphological characterisations like PXRD, FTIR, Raman spectroscopy, SEM, and BET studies were performed for filler and PVDF composites. The dielectric and humidity sensing studies were performed for different weight % of PVDF/graphite (PVDF/G), PVDF/graphene oxide (PVDF/GO) and PVDF/reduced graphene oxide (PVDF/rGO) composites. The alternating current (AC) response studies were measured in the range of 100Hz to 10MHz. The increased AC conductivity of 15 wt% PVDF/rGO composite has shown two order magnitude changes compared with pure PVDF film. Among the composites, 15 wt% PVDF/rGO composite has shown enhanced conductivity of 7.38 x 10-4 Scm-1 and dielectric constant of 1.6023. In the humidity sensing studies, the composite film was prepared by drop-casting the composite resin on the interdigitated electrode (IDE) patterns. Among the composites, 1 wt% PVDF /rGO composite has depicted an improved sensing response, good response of 4 s and recovery time of 6 s and consistent repeatability. The mechanism for sensing has been discussed based on the formation of chemisorption, physisorption and capillary condensation process.
Keyword: Graphite; Graphene oxide; reduced graphene oxide; Poly vinylidene fluoride; dielectric; humidity sensing.
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