| dc.description.abstract | Under 3D confinement generated through a micro-emulsion approach, block copolymer (BCP) tends to form micro spheres with onion-like nanodomains, ellipsoids with axially-stacked nanolamellae, and Oblate particles with nanocylinders. Such hierarchical (structure-within-structure) structures have potential applications in many fields, including biomedicine, energy, catalyst and optical devices. For the micro Emulsion approach, two immiscible solvents, chloroform and water, with different surface properties were used to produce BCP microstructures. PS-b-P4VP was dissolved in chloroform followed by the addition of a large amount of
water with surfactant CTAB. In the presence of CTAB, the solution of PS-b-P4VP/chloroform was emulsified to form colloidal microparicles in the mixture after adding water. Upon removal of chloroform and water, PS-b-P4VP spontaneously self-assembled to form nanodomains within the
microparicles. Under 3D confinement, self-assembly of PS-b-P4VP produced several structure-within-structure morphologies, which could by tailored by controls over molecular weight, solvent quality, as well as the surface energy of BCPs. As a result, onion-like, convex-concavo, and
convex-convex microparticles or oblate mciroparticles with hexagonal arrays of nanopores were obtained. The hierarchical structures were then used as templates to fabricate carbon and metal materials with replicated morphologies for oxygen reduction reactions. | en_US |