Progressive morphology development to produce multilayer films and interpenetrating blends by chaotic mixing

Chaotic mixing of immiscible binary components was recently used in a continuous flow process to obtain extruded films with very many internal layers. Where interfacial tension is small, individual layer thicknesses can be only tens of nanometers and many thousands of continuous or broken layers can be formed. Such materials are both novel and potentially important. In this study, multilayer film formation and breakup were investigated systematically by using a batch chaotic mixer to better understand the more industrially relevant continuous flow counterpart. Polystyrene (PS) and low-density polyethylene (LDPE) were used as a model binary system with appreciable interfacial tension such that comparatively thicker layers and larger breakup bodies were formed and more readily examined. The multilayer film morphology developed progressively as chaotic mixing continued and was thereby amenable to control and optimization with regard to layer thickness and number. Blends with single or dual phase continuity and structured droplet distributions were found to be important derivative morphologies upon layer breakup. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 1569–1579, 2001