http://sfp.grenoble.cnrs.fr/spip.php?page=evenement&id_evenement=5072

DA VEGA

Grenoble

Conferencia; Conferencia invitada ILL Grenoble, Francia; 2018

ILL Grenoble, Francia

Ordered phases lying on curved backgrounds are not only commonly found in nature insystems like viral capsids, pollen grains or the silica skeletons of unicellular algaes but theycan be also obtained in different experimental systems, like self-assembling colloidalparticles, block copolymers or liquid crystals [1-3]. In these curved systems, it was foundthat non-Euclidean geometry could stabilize exotic defects to alleviate the stress imposedby the curvature and to reduce geometric frustration [2].Here we employed a Brazovskii free energy model and self-consistent field theory (SCFT)calculations to analyze the coupling between the smectic textures developed by cylinderforming block copolymer systems and the curvature of the film [4,5]. For weak curvatures,it was found that the free energy of the block copolymer film follows a Helfrich form, with abending constant that depends on the pattern orientation with regard to the directions ofmain curvature. The strong anisotropy in the bending constant explains the maingeometrical features of the out-of-plane deformations observed in free-standing blockcopolymer membranes, where disclinations act as sources of Gaussian curvature [6]. Theseresults are in very good agreement with experimental data of poly(styrene)-co-poly(ethylene-alt-propylene) free-standing membranes and thin films deposited onto curvedsubstrates.