Fractional defect charges for liquid crystals on cones We study two-dimensional liquid crystals with p-fold rotational symmetry (p-atics) on the surfaces of cones, and find both the ground state(s) and a ladder of quantized metastable states as a function of both the cone angle and the liquid crystal symmetry p. […]
Colloidal clusters from confined self-assembly: Structure – Thermodynamics – Formation kinetics The spontaneous organization of individual building blocks into ordered structures is extensively used in nature and found at all length scales, from crystallization processes, via composite materials, to living cells constituting complex tissue. Understanding the relationship between building blocks, […]
Slimming down through frustration Abstract In many diseases, proteins aggregate into fibers. Why? One could think of molecular reasons, but here we try something more general. We propose that when particles with complex shapes aggregate, geometrical frustration builds up and fibers generically appear. Such a rule could be very useful […]
From cylinder packings to auxetic periodic tensegrity structures Abstract I will present a chiral, triply-periodic tensegrity structure, which displays local reentrant geometry at its vertices. Our tensegrity structure is based on the β−Mn cylinder packing from structural chemistry, and contains all symmetries of the cylinder packing itself. The tensegrity structure is auxetic, as demonstrated by the modelling of a quasi-static extension and compression […]
The Wrinkle-to-Crumple Transition in Thin Elastic Solids Abstract The last decade has seen a renaissance in the buckling of thin elastic solids, in part because of its impact on the mechanics of synthetic skins, biological tissues, textiles, and 2D materials like graphene. Significant effort has been devoted to understanding and […]
Symmetry Making and Breaking in Seeded Syntheses of Metal Nanocrystals Abstract Crystal growth theory predicts that heterogeneous nucleation will occur preferentially at defect sites, such as the vertices rather than the faces of shape-controlled seeds. Platonic metal solids are generally assumed to have vertices with nearly identical chemical potentials, and […]
From viral capsids to self-assembling nanoparticles Abstract: Viruses are examples of biological nanoparticles. They are made of a highly symmetric protein container, the capsid, that contains the nucleic acid and self-assembles from several copies of a single protein. The relative position of the proteins in the capsids is conventionally described […]
Braiding wires using capillary forces Electrical conductors that can carry frequencies of tens of GHz are needed for next-generation telecommunications networks. In principle, such conductors can be made from braided conducting filaments. However, maximizing the current-carrying capacity and minimizing loss requires each filament to have a diameter approximately equal to […]
Biological tissues as mechanical metamaterials In multicellular organisms, properly programmed collective motion is required to form tissues and organs, and this programming breaks down in diseases like cancer. Recent experimental work highlights that some organisms tune the global mechanical properties of a tissue across a fluid-solid transition to allow or […]
Placement and Symmetry of Singularities on Curved Surfaces In various contexts, biological structures resemble regular two-dimensional lattices made from smaller units like macromolecules (on the nanoscale) or cells (on the tissue scale). This regularity carries an inherent elastic energy penalty when the 2D manifold is also required to have intrinsic […]