The mass recognizing property of DLC film for formic acid vapors

The carbon films are prepared by r. f. plasma method with n-butylamine as carbon source. The analysis of Raman spectrosewpy shows that this kind of carbon film has diamond-like structure, and IR spectroscopy measurement indicats that there are SP² bonding, SP³ bonding and amino-group in the film. It is the existence of amino-group and hydrogen atom that cause the amorphous structure and the deformation of bonding to increase, thus leading the Raman spectrum to form a broad absorption band. The quartz crystal microbalance (QCM) deposited with this kind of carbon film as recognizing coating is very sensitive to formic acid vapors. This QCM sensor has good reproducibility, high stability, rapid response and long lifetime.