SWCNTs Modified with Porphyrin Units for Chemical Sensing Applications

AbstractIn the present work the composites of the amide- and glycyl-functionalized porphyrin monomers and single wall carbon nanotubes (SWCNTs) were formulated and then applied as novel sensing materials in a quartz crystal microbalance (QMB) sensor array with an integrated preconcentration unit. Two strategies have been adopted for CNT-porphyrin composites design. In the first approach the electropolymerisation of pyrrole-substituted porphyrin monomers occurred via formation of conjugated positively charged polypyrrole backbone, while negatively charged CNT functionalized with carboxylic groups acted as a polymer dopants. In the second case the CNT-porphyrin composites were chemically synthesized via the amide bond formation between carboxylic groups of functionalized CNTs and amino-substituent of porphyrin or via interaction between glycylsubstituted porphyrin monomers and non-modified CNTs. The application of CNT-porphyrin composites permitted a substantial improvement of the signal to noise ratio and the possibility to measure several analytes odor threshold by QMB sensor array