Smart Conducting PANI/P(St-NIPAM) Particles and Their Switchable Conductivity

Particles with circumstance-responsive conductivity have an appealing performance in constructing sensors. Here, “smart” conducting polyaniline-doped poly(styrene-co-N-isopropylacrylamide) composite spheres, i.e. PANI/P(St-NIPAM) particles, are reported. A series of PANI/P(St-NIPAM) particles can be prepared with different ratios of N-isopropylacrylamide to monomers, i.e. N/M ratios. With the improved N/M ratios in polymerization, the amount of polyaniline (PANI) incorporating into the produced particles increased, resulting in an enhanced conductivity. With the improved N/M ratios, the hydrodynamic diameters of PANI/P(St-NIPAM) particles increased at a low temperature, whereas they decreased at a high temperature; resulting in the enhanced volume-change ability with the increasing poly(N-isopropylacrylamide) (PNIPAM) content in particles. Depending on the temperature-induced volume change, these particles exhibit “smart” conductivity in a homemade device, in which these particles can be used as a temperature-responsive conducting medium to construct an “on–off” circuit, and the switch of an LED lamp can be triggered by temperature. These particles with the smart conducting property provide wide potential applications in sensors, microelectronics, energy storage, and other fields