Dynamics of Ordering of Block Copolymers confined to lie on a curved substrate

VEGA DA

Buenos Aires

Conferencia; At the Frontiers of Condensed Matter IV; 2008

Comite organizador de la conferencia At the Frontiers of Condensed Matter IV

In the last decade there has been a growing interest in the process of phase separation in selforganized thin lms, mainly driven by their nanotechnological applications. Although important advances have been made to obtain ordered patterns into the nanoscale, the slow kinetics of ordering prevents the use of thermal treatments to obtain patterns with long range order [Gomez et al., Phys. Rev. Lett. 97, 188302 (2006)]. Then, dierent experimental methods have been employed to control the degree of order. Recently, there has been an increasing interest in the study of 2D modulated phases on curved surfaces [D. R. Nelson, Nano Lett. 2, 1125 (2002)]. One of the main dierences between planar and curved 2D modulated phases is the nature of topological defects. On at backgrounds, at low temperatures, the topological defects are nontrivial excitations of the ground equilibrium state. On the other hand, the curvature of the substrate can impose a topological requirement that includes defects in the ground state. In this talk we discuss the process of phase separation in thin lm systems of cylinder forming block copolymers con ned to lie on a curved substrate. We observe a coupling between defects and geometry that induces unbinding and self organization of disclination pairs. This open the possibility of a robust mechanism for an accurate control of smectic textures with potential applications to nanotechnology.ve