Faculty Sponsor's Department:
Metallic and semiconducting nanoparticles have attracted increasing attention over the past decades due to their unique optical, electronic and catalytic properties that derive from their small size. In particular, ordered nanoparticle arrays represent an interesting class of metamaterials that have applications in chemical sensing, nanoelectronics and photonics. Currently, the controllable aggregation into these ordered arrays has only been achieved by selectively binding complementary DNA attached to nanoparticle surfaces. However, DNA ligands are limited by their scalability, synthetic availability and processing conditions. In addressing these challenges, our attention was focused on a unique example of synthetic helical self-assembly: the stereocomplex of isotactic (it-) and syndiotactic (st-) poly(methyl methacrylate), PMMA. Two it-PMMA strands and one st-PMMA strand can assemble into the triple-stranded super-helix and thus replace the DNA for controllable aggregation. In this work, we have developed a versatile and scalable synthetic strategy to obtain st- and it- PMMA of various molecular weights with functional chain-ends and attached them to metal and/or semiconductor nanoparticles. We then investigated if complementary st- or it-PMMA nanoparticles could be assembled through stereocomplexation. Spectroscopy, light scattering and electron microscopy techniques are used to analyse the assemblage and preliminary results suggest a size dependent assemblage of the nanoparticles. This stereocomplexation has specificity and reversibility that offer facile pathways to form unique nanostructures.