title: Phase behavior and structure of a new colloidal model system of bowl-shaped particles.
abstract: We study the phase behavior of bowl-shaped (nano)particles using confocal microscopy and computer simulations. Experimentally, we find the formation of a wormlike fluid phase in which the bowl-shaped particles have a strong tendency to stack on top of each other. However, using free energy calculations in computer simulations, we show that the wormlike phase is out-of-equilibrium and that the columnar phase is thermodynamically stable for sufficiently deep bowls and high densities. In addition, we employ a novel technique based on simulated annealing to predict the crystal structures for shallow bowls. We find four exotic new crystal structures and we determine their region of stability using free energy calculations. We discuss the implications of our results for the development of materials consisting of molecular mesogens or nanoparticles.
authors.affiliation: Soft Condensed Matter, Debye Institute for NanoMaterials Science, Utrecht University, Princetonplein 5, Utrecht, The Netherlands.
authors.forename: Matthieu
authors.initials: M
authors.lastname: Marechal
authors.forename: Rob J
authors.initials: RJ
authors.lastname: Kortschot
authors.forename: Ahmet Faik
authors.initials: AF
authors.lastname: Demirörs
authors.forename: Arnout
authors.initials: A
authors.lastname: Imhof
authors.forename: Marjolein
authors.initials: M
authors.lastname: Dijkstra
mesh_terms: D003102:Colloids / Q000737:chemistry; D003198:Computer Simulation; D003460:Crystallization / Q000379:methods*; D046911:Macromolecular Substances / Q000737:chemistry; D008422:Materials Testing; D008956:Models, Chemical; D008958:Models, Molecular; D008968:Molecular Conformation; D049329:Nanostructures / Q000737:chemistry* / Q000648:ultrastructure*; D036103:Nanotechnology / Q000379:methods*; D010316:Particle Size; D013499:Surface Properties
chemical_list: D003102:Colloids; D046911:Macromolecular Substances