Purely entropic self-assembly of the bicontinuous Ia3d gyroid phase in equilibrium hard-pear systems

Journal article

Publication Details

Author(s): Schoenhoefer PWA, Ellison LJ, Marechal M, Cleaver DJ, Schroder-Turk GE
Journal: Interface Focus
Publication year: 2017
Volume: 7
Journal issue: 4
ISSN: 2042-8901
eISSN: 2042-8898


We investigate a model of hard pear-shaped particles which forms the bicontinuous Ia[Formula: see text]d structure by entropic self-assembly, extending the previous observations of Barmes et~al. (2003 Phys. Rev. E 68, 021708. (doi:10.1103/PhysRevE.68.021708)) and Ellison et~al. (2006 Phys. Rev. Lett. 97, 237801. (doi:10.1103/PhysRevLett.97.237801)). We specifically provide the complete phase diagram of this system, with global density and particle shape as the two variable parameters, incorporating the gyroid phase as well as disordered isotropic, smectic and nematic phases. The phase diagram is obtained by two methods, one being a compression-decompression study and the other being a continuous change of the particle shape parameter at constant density. Additionally, we probe the mechanism by which interdigitating sheets of pears in these systems create surfaces with negative Gauss curvature, which is needed to form the gyroid minimal surface. This is achieved by the use of Voronoi tessellation, whereby both the shape and volume of Voronoi cells can be assessed in regard to the local Gauss curvature of the gyroid minimal surface. Through this, we show that the mechanisms prevalent in this entropy-driven system differ from those found in systems which form gyroid structures in nature (lipid bilayers) and from synthesized materials (di-block copolymers) and where the formation of the gyroid is enthalpically driven. We further argue that the gyroid phase formed in these systems is a realization of a modulated splay-bend phase in which the conventional nematic has been predicted to be destabilized at the mesoscale due to molecular-scale coupling of polar and orientational degrees of freedom.

FAU Authors / FAU Editors

Marechal, Mattheus Dr.
Lehrstuhl für Theoretische Physik

Additional Organisation
Exzellenz-Cluster Engineering of Advanced Materials

External institutions with authors

Murdoch University
Sheffield Hallam University

Research Fields

A3 Multiscale Modeling and Simulation
Exzellenz-Cluster Engineering of Advanced Materials

How to cite

Schoenhoefer, P.W.A., Ellison, L.J., Marechal, M., Cleaver, D.J., & Schroder-Turk, G.E. (2017). Purely entropic self-assembly of the bicontinuous Ia3d gyroid phase in equilibrium hard-pear systems. Interface Focus, 7(4). https://dx.doi.org/10.1098/rsfs.2016.0161

Schoenhoefer, Philipp W. A., et al. "Purely entropic self-assembly of the bicontinuous Ia3d gyroid phase in equilibrium hard-pear systems." Interface Focus 7.4 (2017).


Last updated on 2019-13-03 at 10:32