Smart self-adjustment of surface micelles of an amphiphilic block copolymer to nanoscopic pattern boundaries

A study was conducted to control the structural symmetry and periodicity of a self-assembled block copolymer in a nanopattern template. Block copolymers show nano-sized structures and have the ability to undergo morphological reformation under various external fields. A method was analyzed, which was based on confining surface pinned micelles consisting of poly(styrene-block-4- hydroxystyrene) (PS-b-PHOST) onto topographically patterned silicon oxide substrates. The PHOST blocks have strong affinity to the substrate through the hydrogen bonding between hydroxyl groups of PHOST and the oxide surface. Atomic force microscopy (AFM) was employed to determine the surface morphology and height variation of copolymers. A dynamic Monte Carlo (MC) method was used to simulate the system of polymer chains grafted to a solid surface. Results show that topographic pre-pattern allows precise control of spatial arrangement of pinned micelles that enables the fabrication of periodic nano-arrays.