Adsorption study of organic molecules on fullerene with piezoelectric crystal detection system

An oscillating piezoelectric quartz crystal membrane coated with fullerene (C-60) provided with a computer interface for signal processing was prepared to study the adsorption and interaction between various organic molecules and fullerene. The affinity of C-60 to various organic vapours, e.g. aldehyde, ketones, carboxylic acids, amines, alcohols, dithiols, alkenes and alkynes was investigated with the C-60-coated piezoelectric gas detector. The selectivity of C-60 for various polar organic molecules seems to be in the order: carboxylic acids>aldehydes>amines>alcohols>ketones. The reversibility of the piezoelectric crystal frequency response curve due to desorption and the IR spectrum were utilized to investigate the interaction between fullerene and these organic molecules. Among polar organic molecules, only amines and dithiols seem to exhibit chemisorption (chemical adsorption) on fullerene while physical adsorption is found in all other cases. For nonpolar organic molecules, alkynes generally exhibited much better adsorption on fullerene than alkenes or alkanes. Chemisorption on fullerene was also observed in the cases of alkynes and 1,3-dienes. Effects of carbon chains, steric structures and isomers of organic molecules on adsorption and frequency responses were also investigated and discussed. (C) 1998 Elsevier Science B.V. All rights reserved.