Towards miniaturized pH sensor based on carbon nanotubes assembled by DEP on titanium electrodes?

In this paper, the pH response of a chemiresistor based on single walled carbon nanotubes (SWNT) was studied. SWNT functionalized with carboxylic groups (COOH-SWNT) were assembled by dielectrophoresis (DEP) between titanium electrodes. Current-voltage I (V) characteristics show that the device conductance decreases as the solution pH increases. DEP enabled to fabricate micronic size structures with low amounts of carbon nanotubes by comparison with SWNT dense films. These structures yielded responses to pH variations.