Anti-icing mechanism of an environmentally sustainable tenebrio molitor antifreeze protein modified asphalt binder via molecular dynamics simulations

Abstract

Environmentally friendly and available tenebrio molitor antifreeze protein (TmAFP) is capable of retarding ice growth. For optimally automatic anti-icing performance in asphalt pavement, environmentally sustainable TmAFP modified asphalt binder is innovatively proposed. Anti-icing feasibility of TmAFP modified asphalt binder is comprehensively investigated via molecular dynamics (MD) simulations including conformational stability, melting temperature, inhibition effect of ice growth and binding free energy between TmAFP and asphalt molecules in various temperatures. It is the first attempt that fully atomistic molecular dynamics simulations on the TmAFP modified asphalt binder are conducted, indicating that the stable binding of TmAFP to ice is attributed to hydrogen bonds originating from the hydroxyl group in the side chain carboxyl group of the threonine (Thr) residue and the amine group of the cysteine (Cys) residue in the β-sheets of TmAFP. Meanwhile, Gibbs-Thomson effect is also observed in the Ice-TmAFP-Water system, which contributes to retard ice growth. The calculation of binding free energy has revealed that TmAFP has the greatest affinity with resin in asphalt molecules, followed by asphaltene and saturation. Furthermore, the van der Waals effect and non-polar interactions are the main contributors to the binding stability of TmAFP and asphalt molecules. Overall, the results provide an efficient avenue to design the preparation of environmentally sustainable TmAFP modified asphalt binder in the laboratory, which have great potential in designing high-performance automatic anti-icing asphalt pavement.