Perylene bisimide metal complexes as new MWCNTs dispersants: Role of the metal ion in stability and temperature sensing

We report on new dispersants based on metal complexes of an extended polycylic aromatic perylene bisimides (PeryC_M), suitable for the exfoliation of MWCNTs. The formal 1:1 metal complexes provided well-disentangled and undamaged MWCNTs and with a content at least 35 wt.% higher than that given by the bare ligand. The ionic charges at the periphery of PeryC_M endowed the π − conjugated perylene core with electrostatic repulsions, thus enhancing MWCNTs dispersibility. MWCNT-based mixtures displayed electrical resistance depending on the MWCNTs content and a typical semiconducting (activated) electrical transport with decreased resistance when heated within the physiological temperature range, i.e. from 20 to 40 °C. While perypheral charges are meaningful for MWCNTs deboundling and stabilization, they do not play any significant role in determining resistance sensitivity to temperature variations within the physiological regime. A negative temperature coefficient of about 10−2 K−1 and comparable to that of common thermistors was found for the investigated sensors.