p-phthalimidobenzoic thin film for volatile organic vapor detection

Thin films of the molecule of p-phthalimidobenzoic acid (FIBA) have been deposited by spin coating and are studied for application as sensing membrane for the detection of alcohols. Atomic force microscopy (AFM) and surface plasmon resosnance (SPR) were used for the characterisation of the FIBA films. Alcohol sensing properties of the obtained films were examined using SPR measurements. AFM images show that FIBA films have the large surface roughness with an estimated roughness RMS value of 6.3 nm. Films with such compact and granular morphology are believed to provide improved sensitivity when used in sensor applications. The measured SPR curves were analysed by applying a least square fitting procedure using Fresnel's reflection theory. FIBA film used as a sensing element for the detection of saturated 2-propanol, ethanol and methanol vapors. Fast response and recovery for all studied analytes have been obtained. These results show that thin films made with this FIBA molecule are demonstrating good suitability for room temperature vapor application.