Multilayer co-extrusion has been utilized to produce novel materials with enhanced mechanical properties through selective manipulation of layer thicknesses and volume compositions. Forced assembly via layer multiplication offers the unique opportunity to directly probe the relationship between structural development and deformation behavior under confined conditions. Two systems have been investigated: 1) an elastomeric block copolymer (BCP) layered with a rigid thermoplastic (interacting and non-interacting), and 2) a semicrystalline polymer layered with high glass transition temperature polymer. In the confined BCP system, we have shown a layer thickness dependence on the deformation mechanics of the multilayer films through tensile experiments with visual confirmation through confocal and optical microscopy studies. As the layer thickness is decreased, a shift from crazing to shear banding is observed with a corresponding increase in extensibility and toughness. For the semicrystalline multilayer films, the deformation behavior was observed to shfit from typical axial alignment of the crystalline fraction in the thicker layers to non-uniform mechanics and micronecking mechanisms in the thinner layers. Preliminary studies of interfacial assembly and connections to barrier technology have also been explored.

Combining forced-assembly and self-assembly to generate mechanically-enhanced, multi-functional materials

242nd National Meeting (2011)

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