Study on chitosan thin film for vapour sensor application

Abstract

The aim of this project is to analyse the electrical properties of the chitosan film sensor exposed to water, methanol and toluene. Chitosan film has proven to be potential as reliable sensor for methanol and toluene detector. The exposure of methanol and toluene with four concentrations 0.1, 0.5, LO and 2.0cc into chitosan is to study the sensitivity and selectivity of chitosan film sensor upon methanol, toluene and water. Electrochemical deposition method has been chosen as a method to fabricate chitosan film. Electrical testing was done to study the sensing properties such as sensitivity, respond time, recovery, stability, repeatability, selectivity and reproducibility has been done in order to fulfill a requirement chitosan film sensor as reliable sensor. Characterization testing which include Atomic Force Microscopy (AFM), Scanning Electrons Microscopy (SEM) and Fourier Transform Infrared Spectrometry (FT-IR) bas been performed to study the microstructure of chitosan film sensor. From the results, the best chitosan concentration to fabricate chitosan film sensor is 1.75 w/v%. Chitosan film after exposed to methanol shows higher output voltage than chitosan film after exposed to toluene. It indicates chitosan film is more sensitive to methanol than toluene. SEM and AFM irnages of chitosan films show compact and smooth surface which indicates homogeneity of chitosan film surface. FT-IR shows the presence of the domain functional group in either chitosan film before or after exposed to methanol and toluene. Thus chitosan film is potential as a reliable sensor because it has high sensitivity, rapid response, stable, good recovery, repeatable and selective to water, methanol and toluene.