Departmental Seminar

Geometry and Crystalline Structure

Professor Michael O'Keeffe
Chemistry, Arizona State University)
Thursday 20 March 2014 9am–12.30pm
Room 3.17, Level 3, Le Couteur Building

9:00am Periodic nets and tilings and the design of porous materials
Michael O’Keeffe (Chemistry, Arizona State University)


9.45am Geometrical Frustration in Amorphous and Partially Crystallized Packings of Spheres
Nicolas François & Mohammed Sadaatfar (RSPE, ANU)

Abstract: We study the persistence of a geometrically frustrated local order inside partially crystallized packings of equal-sized spheres. Measurements by x-ray tomography reveal previously unseen grain scale rearrangements occurring inside large three-dimensional packings as they crystallize.

10.15am - Coffee

10.45am Structure from Shapes
Olaf Delgado-Friedrichs (RSPE, ANU)

Abstract: I will report on recent work with Vanessa Robins and Adrian Sheppard that applies discrete Morse theory to three-dimensional image analysis and try to draw connections to the study of periodic nets and tilings. 

11.25am Complex hierarchically ordered structures in block copolymer melts
Jacob Kirkensgaard (Niels Bohr Institute, Copenhagen University)

Abstract: I will talk about simulation work addressing the role of molecular architecture in the formation of complex morphologies with order on more than one length scale, spiced with available evidence from experimental systems.


11.55am The tricontinuous 3ths(5) phase: A new network morphology in copolymer melts
Gerd Schroeder-Turk (Friedrich-Alexander-Universität, Erlangen)

Abstract: We use numerical self-consistent field theory simulations to show that a triply-periodic tricontinuous structure, called 3ths(5) and based on the intergrowth of three distorted ths nets, is an equilibrium phase of star-shaped triblock copolymers when a fourth component, an extended molecular core, is introduced.This confirms the geometric intuition that the introduction of the core destabilises the hexagonal columnar phase in favour of the 3ths(5) structure by enhancing the role of chain stretching, hence favouring arrangements of the cores on close packed lattices of lines with less packing frustration.

12.35 - Lunch

Contact

Ms Martina Landsmann
martina.landsmann@anu.edu.au

Updated:  17 August 2017/ Responsible Officer:  Head of Department/ Page Contact:  Physics Webmaster