| Böker, A.; Schmidt, K.: Orienting and Tuning Block Copolymer Nanostructures with Electric Fields in U. Steiner, Y. Tsori: Series in Soft Condensed Matter (Vol. 2), Polymers, liquids and colloids in electric fields, World Scientific, 215-244 (2009) | |
| Abstract: In the first part of this chapter, we discuss the origin of the electric field driven alignment of block copolymer nanostructures in solution. We followed the reorientation kinetics of various model block copolymer solutions exposed to an external electric d.c. field. The characteristic time constants follow a power law indicating that the reorientation is driven by a decrease in electrostatic energy. Moreover, the observed exponent suggests an activated process in line with the expectations for a nucleation and growth process. When properly scaled, the data collapse onto a single master curve spanning several orders of magnitude both in reduced time and in reduced energy. In the second part, we show that electric d.c. 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 polarizabilities and permanent dipole moment of the monomeric constituents. Series in Soft Condensed Matter (Vol. 2): Polymers, liquids and colloids in electric fields  |
Sonderforschungsbereich 481
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