Multisensor array of mass microbalances for chemical detection based on resonant piezo-layers of screen-printed PZT

Original mass-microbalance sensors for gravimetric chemical detection are p resented which are based on thickness-mode piezoelectric composite resonato rs made by lead zirconate titanate (PZT) films screen-printed on alumina su bstrate. By exploiting a cheap and affordable technology, such devices easi ly enable to manufacture gravimetric multisensor arrays on the same substra te: This is demonstrated by the presented four-sensor array manufactured on a 25 X 25 mm(2) substrate, which also incorporates a thermostating element to minimize thermal drift. The resonators operate around 7 MHz and have a mass sensitivity in the order of 500 Hz/mu g. The operating principle and s ensor structure is described, and experimental results are reported relativ e to the sensors covered with purposely prepared polymeric coatings and exp osed to hydrocarbon vapours (toluene and hexane) and SO2. (C) 2000 Elsevier Science S.A. All rights reserved.