CAREER: Block Copolymer/layered Silicate Nanocomposites: Thermodynamics, Dynamics, and Structure-Property Relationships

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ARRA STATEMENT:This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).TECHNICAL SUMMARY:This CAREER award supports a project to explore a new class of polymer composites, comprised of block copolymers densely grafted to the surfaces of highly exfoliated layered silicate particles. The PI hypothesizes that this novel class of materials, block copolymer/layered silicates (BCPLSs), holds the potential to lead to high performance/high service temperature polyolefin-based engineering thermoplastics with unprecedented materials properties, arising from a synergistic combination of factors: Mechanical reinforcement provided by the silicate particles, enhanced thermal properties arising perturbations to the chain-conformations, and the ability of block copolymers to stitch multiple materials properties into a single compound. In BCPLS materials each filler particle is intimately coupled to a dense brush of polymer chains; consequently, emergent properties arise not only from mechanical reinforcement mechanisms but also intrinsic perturbations to conformational characteristics of the polymer chain. The use of block copolymers is advantageous since this imparts to the system the inherent tunability of these fascinating materials through the choice of constituent blocks and block sequences, and brings high degrees of processability above the order-disorder transition. Moreover, the confinement of BCPs to the opposing faces of discrete layered silicate particles fundamentally changes the thermodynamics of self-assembly and the resultant morphologies. This unique combination of features is currently absent from the community, and this research is an important opportunity to make seminal contributions to the fundamental understanding and utilization of these new materials.NON-TECHNICAL SUMMARY:This CAREER award supports a project to explore a new class of polymer composites, comprised of block copolymers densely grafted to the surfaces of highly exfoliated layered silicate particles. The PI hypothesizes that this novel class of materials, block copolymer/layered silicates (BCPLSs), holds the potential to lead to high performance/high service temperature polyolefin-based engineering thermoplastics with unprecedented materials properties. In BCPLS materials each filler particle is intimately coupled to a dense brush of polymer chains, eliminating particle aggregation and enhancing the properties by constraining the conformations of the polymer chains, in addition to well-known composite reinforcement mechanisms. This project will generate the fundamental knowledge needed to harness the potential of these materials. Another important objective is to heighten awareness of and interest in STEM careers at the K?12 level. This will be accomplished by integrating this research into an on-campus program for mentoring K?12 science teachers, and the collaborative development of interactive workshops to be delivered electronically to K?12 classrooms throughout Iowa using the Iowa Communications Network.