Block Copolymer Surface Reconstuction: A Reversible Route to Nanoporous Films


  • This work was funded in part by the National Science Foundation-supported Material Research Science and Engineering Center (MRSEC) at University of Massachusetts, Amherst (DMR-9400488) and Department of Energy, Office of Energy Sciences (DE-FG02-96ER45), and the Research Experience for Teachers program of MRSEC.


Thin films of block copolymers have been used as templates and scaffolds for the fabrication of arrays of nanostructured materials. In general, a chemical modification of the film or the removal of one of the components by photodegradative methods is required to produce a nanoporous film that serves as a template or scaffold. Here, however, the preferential interaction of one of the components with a solvent is shown to produce a reconstruction of the block copolymer film that, upon drying, leads to the generation of a nanoporous template. The area density of the pores is identical to that of the original copolymer thin film. Since no chemical reactions occurr, the process is fully reversible. Upon heating the copolymer film above its glass-transition temperature, mobility is imparted to the copolymer and the original copolymer film with oriented domains is recovered. The film reconstruction significantly simplifies the generation of nanoporous templates.