Biomimetic Interfacial Control in Polymer Nanocomposites

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DESCRIPTION (provided by applicant): Conventional dental composites are highly filled polymer systems created by in situ polymerization of multifunctional monomers in the presence of a high volume fraction of particulate glass fillers. While these systems enjoy widespread use and are generally effective for restoring dental tissues, significant improvements in mechanical strength, water resistance, wear and other properties are still needed. Nanoparticulate fillers with high aspect ratios offer the potential for significant strength and other property improvements; however the characteristics of the matrix-filler interface are expected to assume an even greater prominence in such systems due to the extremely high filler matrix interfacial area. Thus, new strategies to nanoreinforced dental composites must include great attention to interfacial design as well as shape, size and composition of filler. In this study we propose to develop new dental nanocomposites consisting of TiO2 nanoparticle reinforced dental composites. The oxide nanoparticles will be in the form of spherical, rod-like and sheet-like nanoparticles. In parallel with nanoparticle development, new approaches to interfacial control will be explored that are inspired by marine adhesive proteins that incorporate unusual amino acids that form high strength, reversible and water resistant bonds to TiO2 surfaces. These compounds will be used to design novel cross-linking and initiating agents that link the matrix to the nanoparticle surfaces with high strength and water resistance. The new nanocomposites will be tested for fracture strength, fracture energy, water absorption, and the effect of aging in water on mechanical performance. Thus, important physicochemical properties of these candidate dental nanocomposites will be revealed during this study, with the results serving as a platform for future detailed studies toward utilization of nanoparticulate TiO2 reinforced composites in dentistry.