Schmidt, K.; Schoberth, H. G.; Ruppel, M.; Zettl, H.; Hänsel, H.; Weiss, T.M.; Urban, V.; Krausch, G.; Böker, A.: Reversible Tuning of a Block Copolymer Nanostructure via Electric Fields, Nature Materials, 7, 142 - 145 (2008), doi:10.1038/nmat2068 | |
Abstract: Block copolymers consisting of incompatible components self-assemble into microphase-separated domains yielding highly regular structures with characteristic length scales on the order of several tens of nanometers. Therefore, in the past decades, block copolymers have gained considerable potential for nanotechnological applications, such as in nanostructured networks and membranes, nanoparticle templates, and high-density data storage media. However, the characteristic size of the resulting structures usually is determined by molecular parameters of the constituent polymer molecules and can not easily be adjusted on demand. Here we show that electric DC fields can be used to tune the characteristic spacing of a block copolymer nanostructure with high accuracy by as much as six percent in a fully reversible way on a time scale in the range of several milliseconds. We discuss the influence of various physical parameters on the tuning process and study the time response of the nanostructure on the applied field. A tentative explanation of the observed effect is given based on the anisotropic polarisabilities and permanent dipole moment of the monomeric constituents. This electric field induced effect further enhances the high technological potential of block copolymer based soft lithography applications. link to full text |