Paper Title
Molecular Simulation Model for Characterizing Barrier Coatings on Paper

Abstract
Surface energy and mesoscale surface roughness are two key attributes that determine surface wettability/lipophilicity. Further, gas and moisture permeability of a coating is determined by equilibrium solubility and transport diffusivity of the permeant (O2, H2O, etc.) across the coating.A multitude of formulation components and compositions will make direct experimental screening prohibitive.I will report ondevelopment of a molecular simulation model to allow quick screening for coating formulation compositions. Two unsubstituted starch polymers, amylopectin (36 mers) and amylose (18 mers), were used for placingtrimethylammonium chloride (3-Chloro-2-hydroxypropyl) cations to create cationic starch with a degree of substitution(DS) of 0.035. The simulation protocol was validated by calculating the torsion angle distribution in unsubstituted and substituted chains. Specifically, the torsion angles of the glyosidic linkages wascompared with data from several force fields and the torsion angles at cation substituting site were compared against the density functional theory (DFT) predictions. A simulation box representing a typical 7-8% (w/w) starch solution for coating (amylopectin: 3.65%, amylose: 1.31%; glycerol: 1.46%, water: 93.65% on w/w basis) was prepared. Density and viscosity for this model coating solution were compared with corresponding experimental data. The structure of the paper substrate was created as a crystalline packing of cellulose chain. The paper-coating solution model can be used to characterize barrier properties of a coated paper. Keywords - High Moisutre Barrier; Paper; Starch Coating; Food Packaging; Molecular Simulations