8 ETHANOL SENSING BEHAVIOUR OF TIO2-PVK THIN FILMS

The aim of these research is to investigate the effect of poly(n-vinylcarbozale) (PVK) additions on microstructures and ethanol sensing behaviour of TiO2-PVK composites thin films. Five different ratios of TiO2:PVK solutions were prepared for this experiment. Spin coating technique was employed for deposition of films. SEM and AFM characterization was used for microstructural characterization of the films. For gas sensing test the concept of variation in conductivity of the film was applied. All sensors were exposed towards nitrogen followed by ethanol vapour for gas sensing test. SEM and AFM micrographs indicated that the surface morphology of the films was governed by the amount of PVK additions. Sensor with 4 vol % of PVK was the only device exhibited gas sensing ability. The stability of the sensor reduced with the increment number of exposure cycle. These studies confirmed that composite between TiO2 and PVK able to detect ethanol vapour at room temperature for certain amount of PVK