A temperature sensor based on a MWCNT/SEBS nanocomposite

The fabrication of a temperature sensor based on multi-walled carbon nanotubes (MWCNTs)/styrene-b-(ethylene-co-butylene)-b-styrene (SEBS) triblock copolymer composite is reported. The device was realized by drop casting 10 μl of a MWCNTs dispersion in a toluene solution of SEBS onto gold electrodes fabricated onto a polyimide support. Thermogravimetric and electrical resistance measurements highlighted a good reproducibility of film composition and sensing properties. A negative temperature coefficient with an absolute value comparable to the highest values in metals was measured when a substantial amount of MWCNTs was incorporated into the nanocomposite (40% by weight), and a five-fold increase was observed close to the percolation threshold. Though such sensitivity seems to be partly lost after the first heating, the results allowed us to be optimistic about the feasibility of realizing nanocomposite films with temperature sensitivities comparable to that of common thermistors in the range 20-60 °C.