Self-Organization of FePt Nanoparticles on Photochemically Modified Diblock Copolymer Templates

摘要

Phase-segregated block copolymers have received significant attention in the last decade as enabling materials for future technologies. Their value to nanotechnology derives from the expedient tunability of the size, shape, and periodicity of the self-assembled domains by means of manipulating molecular characteristics. Recently, the potential opportunities for block copolymer applications have been bolstered by new methods, which give fine control over long-range ordering of the microdomain structures. Thin polymer films, by themselves, have limited device applications, but myriad functions can be addressed with hybrid hard/soft matter systems in which the organic layer is used as a scaffold for nanoscale organization of inorganic materials. Of specific interest is the interaction of surfactant-mediated colloidal nanoparticles and diblock copolymer films because the nanocrystal capping molecules can be tailored to exhibit preference for one of the polymer blocks. This hierarchical approach to create ordered nanostructures removes the linear correlation of size and patterning time associated with traditional lithographic techniques by self-assembling the entire surface in parallel. Also, the spatial limits of lithography can be transcended and the approach can potentially be adapted to industrial-scale processing. An alternative approach to the colloidal nanocrystal methodology is to use spherical- or cylindrical- phase diblock copolymers as etch masks to produce self-assembled arrays of nanoscale dots, pillars, or lines composed of various materials. The advantage of our approach is that the length-scale of the final functional material is an order of magnitude smaller than the original polymer domains.