Theoretical study of trimethylamine adsorption on the linear and cyclic polymers and the effect of pore size

From the perspective of food security, human health and diagnose diseases, developing sensing materials with high sensitivity and selectivity to detect TMA is quite essential. In this study, cyclic tetrapyrrole (CTPy), cyclic hexapyrrole (CHPy), cyclic octapyrrole (COPy) and linear hexapyrrole (LHPy) are selected to investigate the effects of cyclic and linear polymers, as well as the pore size of cyclic polymers on trimethylamine (TMA) gas sensitivity performance. The calculation results show that CHPy with appropriate pore size provides more interaction sites, and exhibits larger adsorption energy, ideal recovery time, as well as significant variation of energy gap and work function after TMA gas adsorption, indicting CHPy is a promising reusable resistance and work function-type sensors at room temperature. Meanwhile, CHPy exhibits better selectivity for TMA gas under the humidity, background gas and other amine gases environment. Furthermore, applied positive electric field can further enhance the selectivity and sensitivity of CHPy toward TMA gas. This work provides some inspiration for experimenters to design and synthesize highly sensitive polymer-based sensors in future experiments.