Stereo-regulated Schiff base siloxane polymer coated QCM sensor for amine vapor detection

Stereo-regulated siloxane film was prepared from the Schiff base of 3-(aminopropyl)triethoxysilane(APTES) and organic compounds having keto group by condensation reaction. The organic compounds such as benzaldehyde, acetophenone, heptaldehyde and camphor were chosen for making various sizes of pores in polymer films. The film was coated on quartz crystal microbalance (QCM) surface for the detection of aliphatic amine vapors such as methylamine, ethylamine, diethylamine, triethylamine, tert-butylamine and ammonia. The structures, morphology and surface roughness of films were studied by FTIR, FESEM and AFM respectively. It was noticed that, the film prepared from camphor has the highest sensitivity for the detection of amines which was due to the bulky globular structure of the camphor molecule by producing reasonable pores of desired size. The polymer film obtained from camphor and APTES was highest sensitivity and fast response towards the detection of organic amine vapors. The linearity of detection was measured up to 250 ppm and the sensitivity of the sensor was found to be 1.20-2.59 Hz/ppm.