Polyurethane acrylate/multiwall carbon nanotube composites as temperature and gas sensors: Fabrication, characterization, and simulation

Polyurethane acrylate (PUA)/multiwall carbon nanotube (MWCNT) nanocomposites with potential applications in printable semiconductors were studied. For this purpose, first, the modification process of MWCNTs was performed by Feridel-Crafts acylation, then, polymerizable functional groups were connected to their external walls. After that, polyurethane pre-polymers with acrylic group ends were manufactured, and finally, the intended nanocomposites were obtained by optimum emulsion polymerization with the help of ultrasonic waves. The dispersion manner and structural specifications of MWCNTs and their interaction with polymer chains were investigated by transmission electron microscopy. The electrical conductivity property of the obtained nanocomposites with different quantities of MWCNTs as a function of temperature was studied as well and a linear relationship was attained at 1 wt% of MWCNTs. In addition, the role of polymer-based semiconducting nanocomposites for temperature sensing was discussed, and the sensitivity of the prepared temperature sensor was found to be about 0.102 M Omega/degrees C. In addition, the Monte Carlo simulation of this nanocomposite was performed for sensing the various gases such as H-2, NO2, and NH3. In gas adsorption NO2, the adsorption energy of the PUA/3 wt% MWCNTs composite was about 50% higher than that of pure PUA. It was shown that this nanocomposite can also be used as an appropriate gas sensor, particularly for NO2 gas.