To guarantee good mechanical and optical properties of coating products, it is important to control molecular orientation of polymer chains in liquids to be coated on the web or substrate. In this study, Brownian dynamics (BD) and the conventional computational flow dynamics (CFD) simulations have been incorporated to elucidate dynamics and conformation of a polymer molecule in coating flow regime. Flexible polymer chain, e.g., -DNA molecule here, changes its conformation, relying on its flow strength (Weissenberg number, Wi) and flow type parameter (). Interestingly, in slot coating flow, the chain can be more extended by the extension-like flow field near the downstream free surface curvature. Due to the complex flow field within the slot coating bead region, the extensibility of polymer chain moving along the streamline has also been investigated by correlating with the effective Wieff and process conditions such as coating gap, web speed, and so on.
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