Microlayer and Nanolayer Polymeric Materials

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Layer-multiplying technology will be used to fabricate unique structures of otherwise incompatible polymers. In contrast to the well-known concept of self-assembly, layer multiplication uses forced-assembly to create thousands of alternating nanolayers of two polymers with individual layer thickness less than 10 nm. The assemblies of thousands of continuous polymer nanolayers fabricated by this method are easily handled and are amenable to characterization by conventional methods of polymer analysis. This allows us to probe phenomena that occur only on the size scale of the macromolecule, and to fabricate new materials that incorporate the unique properties of this size scale. The proposed research intends to: (1) Explore the polymer "interphase" that forms when two immiscible polymers are brought into intimate contact, and create new materials based on the unique properties of the "interphase"; (2) Explore crystallization of polymers in confined nanolayer spaces; (3) Investigate melt breakup of nanolayers into nanodroplets, and subsequent fractionated nucleation and crystallization of nanodroplets; and (4) Create nanofibers and nonoporous membranes by orientation of nanolayered films.Motivated by the need for new processing technologies to develop the engineered nanstructures of the future, a facility for layer-multiplying coextrusion was developed at Case Western Reserve University. The laboratory at CWRU is the only facility at a public institution with the processing flexibility needed to explore the wide range of new materials systems possible with this technology. The graduate and undergraduate students that participate in the research will have the opportunity to use a unique coextrusion process, to address fundamental problems related to the behavior of polymers at the nanoscale, and to design and realize materials systems that were not possible previously. Through written and oral communications, the fundamental insights and the unique opportunities provided by this versatile technology will be translated to the field at large, including the industrial sector. Ultimately, nanoprocessing, as exemplified by nanolayer coextrusion, can be the basis for creating "smart" materials with multiple functions. Fabrication of tough films and sheet that possess specific optical properties, and additionally exhibit barrier characteristics or unusual electronic properties, seems possible.