Characterization and gas sensing properties of langmuir-blodgett thin films of poly(CINOEMA-co-DEAEMA

Abstract

2-(4-chloro-1-naphtyloxy)-2-oxoethyl methacrylate (CINOEMA) was synthesized by reacting 4-Chloro-1-naphthyloxychloromethylketonewith sodiummethacrylate in acetonitrile solvent at 70 °C. The free-radical initiated copolymerization of (CINOEMA), with 2-(diethylamino)ethyl methacrylate (DEAEMA) was carried out in 1,4-dioxane solution at 70 ±1 °C using 2,2'-azobisisobutyronitrile (AIBN) as an initiator with 50%-50% monomer-to-monomer ratio in the feed. The Langmuir-Blodgett (LB) thin film fabrication and gas sensing properties of this poly(CINOEMA-co-DEAEMA) is reported in this study. LB deposition process is characterized by UV-visible spectroscopy and quartz crystal microbalance (QCM) technique. The typical frequency shift per layer is obtained as 34.50 Hz/layer and the deposited mass onto a quartz crystal is calculated as 1267.43 ng/layer. Gas sensing properties of these LB films against five different volatile organic compounds (VOCs) are studied using the QCM technique. The poly(CINOEMA-co-DEAEMA) LB film sensor sensitivities are determined to be between 0.021 and 0.055 Hz ppm-1. Detection limits are found to be between 108.89 and 277.78 ppm against vapors. LB films are more sensitive to dichloromethane and chloroform than other vapors used in this study. The poly(CINOEMA-co-DEAEMA) material is promising as a vapor sensing device at room temperature.