= 아 래 =
1. 일 시 : 2012. 9. 7 (금), 13:30 ~15:00
2. 장 소 : 자연과학동(E6) 1층 공동강의실(1501호)
3. 연 사 : Professor. Thomas P. Russell (Department of Polymer Science & Engineering, University of Massachusetts)
4. 제 목 : From Ultradense Arrays of Nanodots to Nanolines : A Route to Addressable Media
As the size scale of features continue to shrink in devices, the use of self-assembly, i.e. a “bottom up” approach, for device fabrication becomes increasingly important. Yet, simple self-assembly alone will not be sufficient to meet the increasing demands place on the registry of structures, particularly nanostructured materials. Several criteria are key in the rapid advancement and technology transfer for self-assembling systems. Specifically, the assembly processes must be compatible with current “top down” approaches, where standard photolithographic processes are used for device fabrication. Secondly, simple routes must be available to induce long-range order, in either two or three dimensions, in a rapid, robust and reliable manner. Thirdly, the in-plane orientation and, therefore, ordering of the structures, must be susceptible to a biasing by an external, macroscopic means in at least one, if not two directions, so that individual elements can be accessed in a reliable manner. Block copolymers, specifically block copolymers having a cylindrical microdomain morphology, are one such material that satisfy many, if not all, of the criteria that will be necessary for device fabrication. A simple, versatile approach to the directed self-assembly of block copolymers into a macroscopic array of unidirectionally aligned cylindrical microdomains on reconstructed faceted single crystal surfaces or on flexible, inexpensive polymeric replicas was discovered. High fidelity pattern transfer to a master mold is shown. The exceptional alignment arises from entropic penalties of chain packing in the facets coupled with the bending modulus of the cylindrical microdomains. The atomic crystalline ordering of the substrate is transferred, over multiple length scales, to the block copolymer microdomains, opening avenues to large-scale roll-to-roll-type and nanoimprint processing of perfectly patterned surfaces and as templates and scaffolds for nanowire arrays.