Molecular simulation on thermal conductivity and mechanical properties of ternary nanocomposites of polyaniline/polypyrrole/graphyne modified with N atoms

To effectively utilise dissipated thermal energy, thermoelectric materials were used to carry out direct thermoelectric conversion. To construct excellent thermoelectric materials, graphyne (GY) as a novel filler was added into a composite of polyaniline (PANI) and polypyrrole (PPy). To improve its performance, the graphyne sheet was modified with N atoms (NGY). The NGY sheets were set between PANI and PPy matrix layers to build PPy/NGY-n/PANI composites (PPGP-n, n = 0, 0.5, 1.2, 2.0, 4.4, 7.0, 10.0%, adopting atomic percentage). The effects of varying N atom concentrations in GY sheets on the thermal, electronic properties and mechanical properties of PPGP-n nanocomposites were investigated using molecular simulation. The mechanism of thermal conductivity was investigated through the analysis of the Vibrational Power Spectrum (VPS) and interfacial thermal conductance. The electronic properties were evaluated by analysing the HOMO–LUMO energy gap and the electrostatic potential. The tensile properties are discussed by evaluating the relationship between the ultimate strength, interfacial binding energy, and thermal conductivity. In summary, PPGP-n (n ≥ 2%) exhibits low thermal conductivity and excellent mechanical properties. This work demonstrates the significant potential of the PPy/NGY-n/PANI nanocomposite in the thermoelectric field.