Dresden 2017 – wissenschaftliches Programm
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 4: Bioinspired Functional Materials I
CPP 4.7: Vortrag
Montag, 20. März 2017, 12:15–12:30, ZEU 114
The Bicontinuous Gyroid-Phase in Purely Entropic Self-Assembly of Hard Pears — •Philipp Schönhöfer1,2, Laurence Ellison3, Matthieu Marechal2, Douglas Cleaver3, and Gerd Schröder-Turk1 — 1School of Engineering and Information Technology, Murdoch University, Murdoch, Australia — 2Institut für Theoretische Physik I, Universität Erlangen-Nürnberg, Erlangen, Germany — 3Materials and Engineering Research Institute, Sheffield Hallam University, Sheffield, UK
We investigate a model of tapered hard particles reminiscent of pears forming the bicontinuous Ia3d structure by entropic self assembly. Based on the observations of Barmes et al. and Ellison et al. a phase diagram for particles with an aspect ratio k = 3 in relation to the degree of tapering kθ and the tapering angle θ = 2arctan(1/2kθ), respectively, around the gyroid phase is generated. Additionally, the mechanism of interdigitating sheets of pears in these systems to create surfaces with negative Gauss curvature, which is needed to form the gyroid minimal surface is investigated in detail. We show that this mechanism differs from systems, which occur in nature (lipid bilayers) and synthesized materials (di-block copolymers) and where the formation of the gyroid is energetically driven, as for single hard pears do not follow Steiner*s theorem. This behaviour is investigated by Voronoi tessellation, whereas both shape and volume of the Voronoi cells in regard to the gauss curvature of the gyroid surface is determined.
[1] F. Barmes et al., Phys. Rev. E 68, 021708 (2003)
[2] Ellison et al., Phys. Rev. Lett. 97, 237801 (2006)