Enhancement of sensory properties of chemoresistive conductive nanocomposites of carbon nanotubes and polypyrrole by functionalized calixarenes

This work presents for the first time the modification and enhancement of sensory properties of a chemoresistive conductive core-shell nanocomposite of multi-walled carbon nanotubes (MWCNTs) and polypyrrole (PPy) doped by p-toluenesulfonate anions (TS) (MWCNT/PPy-TS) under long ultrasonic treatment in joint dispersions and, hence, under physico-chemical interactions with functionalized calixarenes (CA), namely calix[4]arene methylene-bis-phosphonic acid octasodium salt (CPA) and calix[4]arene sulfonic acid (CSA). The interactions are confirmed by a detailed analysis of FTIR spectra of a parent binary MWCNT/PPy-TS nanocomposite and its counterpart ternary MWCNT/PPy-TS/CA nanocomposites as well as by sensor measurements. The results of the latter show a strong enhancement of the sensitivity of the MWCNT/PPy-TS to isopropanol, acetone and ammonia vapors due to CSA and CPA additives, which, however, depends on the nature of functional groups of these CA.