Effect of various aryl substitutions on the interfacial interaction energy of graphene/conductive polymer nanocomposites

Abstract

Studying intermolecular interactions in polymer nanocomposites is highly effective in achieving high-efficiency nanocomposites. To investigate the polymer nanocomposites including conductive polymers, namely poly (3-phenylhydrazone thiophene) (PPHT), poly (3-(4-n-octyl)-phenylthiophene) (POPT), and functionalized graphene nanosheet (FGN), reactive molecular dynamics (RMD) simulation were employed. The FGN structures were a result of the arylation of graphene nanosheets containing different substitutions including sulfide, amine, di-amine, and thiol functional groups. According to interaction energies at polymers / arylated graphene nanosheet, the most interaction energies resulted in nanocomposites of PPHT/graphene-thiophenyl amine (G-PATP) and POPT/graphene-p-Phenylenediamine (G-PPD). Due to the polarity of PPHT, the formation of hydrogen bonding (H-bonding) was expected at specific sites, which were confirmed based on H-bonding interaction criteria. In reality, the criteria required for detecting H-bonding through RDF and the relevant angle measurement have been established. On the other hand, due to the acidic-sensitive hydrazone bond in PPHT, it was expected that the increasing trend in interaction energy of nanocomposites of PPHT could be solely justified based on the acidity of the functional groups employed. However, based on the obtained results, other factors such as the topological polar surface area (TPSA) and the formation of unconventional H-bonding, in addition to the acidity of functional groups, have been considered as influential factors in the changing of interaction energy. Also, the dynamic behavior of polymers was examined by plotting the radius of the gyration (Rg) parameter via time and functional groups. Finally, the temperature effect on interaction energy was determined, too.