SAW Sensors for Nerve Agents Detection

A modified spin coating method used for fabricating the waveguide layer has been evaluated for Love wave device. The properties of these devices have been compared with those of devices fabricated by the conventional method. The thicker and smooth layers achieved by the modified method enhance the mass sensitivity and reduce the insertion loss. Poly (vinylidene fluoride) (PVDF) and sulfosalicylic acid (SSA) modified Poly (methyl-3,3,3-trifluoropropylsiloxane) (PMTFPS) are used to detect the dimethyl methyl phosphonate (DMMP) vapor, a simulant of nerve agents. Both the QCM sensors based on the two materials show the fast, large, and reversible response against DMMP. A group of hydrogen-bond acidic polymers has been investigated on their sensitivity of DMMP vapor. The experiments show that a polymer with the strongest hydrogen-bond acidic functional group can be the least sensitive one among the studied polymers. It is attributed to the different degree of self-association of the polymers determined by the entanglement of the polymer chains.