The basic principles of acoustic wave sensors are described in a separate chapter on sensor types. Here, special applications in context to chemical analysis are summarized.
The first surface acoustic wave (SAW) chemical sensor was described in 1979 (1). Monographs and reviews dealing with this topic are available (2–6). Recent studies using SAW sensors are summarized in Table 12.1.
|Poly(pyrrole)||H2 and NO2||(7)|
|Fluoropolyol||Dimethyl methylphosponate||(8, 9)|
|Poly(vinyl alcohol)||Humidity||(10, 11)|
A series of polymers have been used to detect gases of various kinds. The state of the art has been reviewed (13) and is summarized in Table 12.2.
SAW gas sensors using nanofibers from poly(pyrrole) as the active component were used for the detection of hydrogen and nitrogen dioxide at room temperature. The nanofibers were synthesized by a template-free chemical route.
The polymerization of pyrrole in the presence of FeCl3 as the oxidizing agent was accelerated by the addition of 2,2′-bipyrrole (7). 2,2′-Bipyrrole was synthesized as shown in Figure 12.1.
An average diameter of the nanofibers ...