title: Linked topological colloids in a nematic host.
abstract: Geometric shape and topology of constituent particles can alter many colloidal properties such as Brownian motion, self-assembly, and phase behavior. Thus far, only single-component building blocks of colloids with connected surfaces have been studied, although topological colloids, with constituent particles shaped as freestanding knots and handlebodies of different genus, have been recently introduced. Here we develop a topological class of colloids shaped as multicomponent links. Using two-photon photopolymerization, we fabricate colloidal microparticle analogs of the classic examples of links studied in the field of topology, the Hopf and Solomon links, which we disperse in nematic fluids that possess orientational ordering of anisotropic rod-like molecules. The surfaces of these particles are treated to impose tangential or perpendicular boundary conditions for the alignment of liquid crystal molecules, so that they generate a host of topologically nontrivial field and defect structures in the dispersing nematic medium, resulting in an elastic coupling between the linked constituents. The interplay between the topologies of surfaces of linked colloids and the molecular alignment field of the nematic host reveals that linking of particle rings with perpendicular boundary conditions is commonly accompanied by linking of closed singular defect loops, laying the foundations for fabricating complex composite materials with interlinking-based structural organization.
authors.affiliation: Department of Physics, University of Colorado Boulder, Boulder, CO 80309; Theory of Inhomogeneous Condensed Matte, Liquid Crystal Materials Research Center, University of Colorado Boulder, Boulder, CO 80309;
authors.forename: Angel
authors.initials: A
authors.lastname: Martinez
authors.affiliation: Department of Physics, University of Colorado Boulder, Boulder, CO 80309;
authors.forename: Leonardo
authors.initials: L
authors.lastname: Hermosillo
authors.affiliation: Max-Planck-Institut für Intelligente Systeme, D-70569 Stuttgart, Germany; IV Institut für Theoretische Physik, Universität Stuttgart, D-70569 Stuttgart, Germany;
authors.forename: Mykola
authors.initials: M
authors.lastname: Tasinkevych
authors.affiliation: Department of Physics, University of Colorado Boulder, Boulder, CO 80309; Theory of Inhomogeneous Condensed Matte, Liquid Crystal Materials Research Center, University of Colorado Boulder, Boulder, CO 80309; Department of Electrical, Computer, and Energy Engineering and Materials Science and Engineering Program, University of Colorado Boulder, Boulder, CO 80309; and Renewable and Sustainable Energy Institute, National Renewable Energy Laboratory and University of Colorado Boulder, Boulder, CO 80309 ivan.smalyukh@colorado.edu.
authors.forename: Ivan I
authors.initials: II
authors.lastname: Smalyukh
keywords: Hopf and Solomon links; liquid crystals; low-dimensional topology; self-assembly; topological defects
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