Use of plasma polymerized highly polar organic compound films for sensor development

This work made use of cleaner technologies and environmental friendly reagents to produce polar organic films with adsorption properties to be used as sensors in the environmental field. The films were obtained by plasma deposition of 2-propanol. The films were characterized by infrared and Raman spectroscopies, contact angle measurements with different aqueous solutions, optical and Atomic Force Microscopies (AFMs). The films were hydrophilic and contact angles formed by drop of water were smaller than 70°. All the films showed affinity for 2-propanol aqueous solutions in a large concentration range (0.01–50 vol.%). The films with higher adsorption capacity were characterized by X-ray photoelectron spectroscopy (XPS). For these films the C/O atomic ratio was 4/1. ilms were analyzed through current–voltage (I–V) and quartz crystal microbalance (QCM) measurements to investigate their application on sensing. It was noticed that there is adsorption and permeation of organic compounds. Therefore, this film can be used as selective membrane for sensors. The results indicated that the adsorption mechanism happens through the superficial OH competition.