文摘
A nanocomposite of multiwalled carbon nanotubes (MWNTs) embedded in poly(2,5-dimethylaniline) (PDMA) was synthesised by oxidative polymerisation. The nanocomposite (PDMA–MWNTs) showed a progressive spontaneous undoping process along the time associated to the instability of the doping agent, constituted by HCl, inside the polymeric matrix. The study of the undoping process revealed that this phenomenon is related to the synergetic effect of the sterical hindrance of the substituents on the aromatic rings and the presence of MWNTs inside the polymeric matrix. The conducting properties connected to a doping–undoping equilibrium in the presence of the doping agent were also investigated. The instability of the doping process allowed us to fabricate a spontaneous reversible sensor for acid vapours by setting up a comparative potentiometric circuit and engineering the sensitive element directly on the circuit board.