Molecular dynamics simulation and performance verification of γ-polyglutamic acid/cold water–soluble starch film formation and permeability

Abstract

Abstract Six types of γ-polyglutamic acid (γ-PGA)/cold water–soluble starch (St) composite-film models were constructed using molecular dynamics simulation, and their properties were investigated and compared with the corresponding experimental values. The compatibility between the composite film componentswas analyzed using the radial distribution function and mean square displacement (MSD). The hydrogen bond number and bond energy were used to track the film-formation process. The mechanical property data of the films were extracted, and MSD was used to analyze the permeability of the film to carbon dioxide, oxygen, water vapor, and carbon-16 saturated fatty acids. Finally, the simulated values of mechanical properties and permeability were compared with the experimental values. The results demonstrated that γ-PGA is well compatible with St. The intramolecular and intermolecular hydrogen bonds of γ-PGA and St did not change considerably during the film-formation process. The simulated values of the mechanical properties exhibited a similar trend as the experimental values; however, in terms of permeability, a difference was observed between the initial values of the simulated design and actual material parameters, as well as the complexity of the experiment.