Suppressing ion aggregation on cellulose surface by bio-dielectric liquids: Insights from molecular dynamics simulations

Abstract

The dielectric liquids/cellulose system has been widely employed to protect industrial devices due to its excellent insulation and heat dissipation properties. Nevertheless, the aggregation of molecules and ions on the cellulose surface has a significant influence on its physical and chemical performances. In this study, the migration characteristics and suppression mechanisms of H2O and H3O+ were studied in bio-based dielectric liquids (BDLs)/cellulose and petroleum-based dielectric liquids (PDLs)/cellulose systems via molecular dynamics (MD) simulations and quantum mechanics (QM) methods. Results indicated that the water molecule was adsorbed unavoidably on the cellulose surface in both systems even though the stronger interaction between H2O and BDLs molecules delayed the transport process. However, the migration suppression of H3O+ was found in BDLs/cellulose systems, which is entirely different from that in PDLs/cellulose systems. The self-assembled structure made the ion be far away from the cellulose surface and never trigging the “driver” procedure, which deciphered that BDLs attenuated the performance degradation of cellulose by inhibiting the transfer of ions. On the contrary, the H3O+ was integrated into cellulose quickly because of the repulsion interaction between PDLs and H3O+. As for suppression mechanisms, the polar groups in BDLs were considered to be the most effective parameter to avoid aggregation of ions on the cellulose surface, since the electrostatic potential was enough to encapsulate ions. This research can provide a more practical reference for the performance prediction and structure design of liquid-solid systems in the future.