Polymerized linseed oil coated quartz crystal microbalance for the detection of volatile organic vapours

Quartz crystal microbalance (QCM) sensors are developed from polymerized linseed oil and used for the detection of volatile organic compounds (VOCs) such as p-cresol, o-xylene, benzene, and toluene. The polymer film on QCM surface is synthesized from the free radical polymerization of linseed oil in chloroform using benzoyl peroxide as initiator by dip coating method. The sensitivity, stability and selectivity of the sensors are measured by exposing the QCM surface to vapours. The synthesis of films are optimized and is found to have maximum adsorption of vapours when it is polymerized with 1.7% (w/v) of benzoyl peroxide. Among these four types of vapours, the maximum sensitivity is found with p-cresol and frequency shift of 110 Hz is obtained for 250 ppm of p-cresol vapour in nitrogen atmosphere. The sensor responses of concentration ranges from 5 to 250 ppm are found to be linear. The structure of the polymeric films is confirmed by FTIR analysis. Surface morphologies of the films before and after absorption are studied using AFM. The sensors are reactivated by releasing the adsorbed vapour by passing dry nitrogen gas. The sensing responses of VOC are observed to be substantial and reproducible.