ORGANIC VAPOR SENSORS BASED ON QUARTZ-CRYSTAL MICROBALANCE COATED WITH SELF-ASSEMBLED MONOLAYERS

Alkanethiols incorporating two different omega-functional groups (HS(C H2)(6)X; X = -OH(I), -OCH2Ph(II)) were coated onto the gold electrodes of quartz crystal microbalance (QCM) via the molecular self-assembly process to afford stable monolayers. The adsorption behaviour and inte raction mechanism of organic vapours on QCM sensors coated with these self-assembled monolayers (SAM) were investigated. The hydrogen bondin g and dipole-induced/dipole interaction between the vapour molecules a nd the coating layer enable excellent response of the sensors to organ ic vapours which bear strong electron attracting groups, such as aceti c acid and alcohols. The response is rapid and the sensors exhibit goo d reversibility owing to the thin monolayer coating film. This work de scribes a convenient and simple method of preparing QCM vapour sensors . (C) 1997 Elsevier Science S.A.