Ph.D Thesis

Ph.D StudentShemesh Ariel
SubjectArtificial Nose for the Detection of Gas Phase Substances
DepartmentDepartment of Chemistry
Supervisors ASSOCIATE PROF. Yoav Eichen


The quality of the air we breathe is a direct measure to our ability to maintain normal daily life. The presence of even small amounts of toxic components in our surrounding atmosphere will result in an almost immediate effect. In some cases, micrograms of the right material will kill us in a matter of seconds. In other cases, the effect of even a single exposure to a hazardous substance will be revealed only after many years. For this reason and because of this venerability, our air is a prime target for terrorists. In parallel, when dealing with simple weapons employed by terrorists, explosives are still in fashion and still represent the main contemporary threat. Detection of explosives at relevant concentrations is still a most challenging task and lags after developments in the field of concealing and camouflage.

This research paves the road towards a chemo-mechanical artificial nose. It combines microcantilevers as highly sensitive mechanical platforms with the rich realm of organic chemistry. The research focuses on cardinal issues, namely, the ways to achieve sensitivity, selectivity, reliability and miniaturization. It examines new methods for singling-out a low-concentration target material out of a rich and concentrated mixture of innocent materials. The research shows that discrimination can be achieved through the educated choice of the sensing layer where the chemical interaction leads to mechanical phenomena. In such a way, isotopologues can be distinguished and nitroaromatics may be identified in the presence of other materials by their tendency to exert mechanical quenching of bending phenomena.