title: Hexadecapolar colloids.
abstract: Outermost occupied electron shells of chemical elements can have symmetries resembling that of monopoles, dipoles, quadrupoles and octupoles corresponding to filled s-, p-, d- and f-orbitals. Theoretically, elements with hexadecapolar outer shells could also exist, but none of the known elements have filled g-orbitals. On the other hand, the research paradigm of 'colloidal atoms' displays complexity of particle behaviour exceeding that of atomic counterparts, which is driven by DNA functionalization, geometric shape and topology and weak external stimuli. Here we describe elastic hexadecapoles formed by polymer microspheres dispersed in a liquid crystal, a nematic fluid of orientationally ordered molecular rods. Because of conically degenerate boundary conditions, the solid microspheres locally perturb the alignment of the nematic host, inducing hexadecapolar distortions that drive anisotropic colloidal interactions. We uncover physical underpinnings of formation of colloidal elastic hexadecapoles and describe the ensuing bonding inaccessible to elastic dipoles, quadrupoles and other nematic colloids studied previously.
authors: Department of Physics and Soft Materials Research Center, University of Colorado, Boulder, Colorado 80309, USA.
authors: Bohdan
authors: B
authors: Senyuk
authors: Department of Physics and Soft Materials Research Center, University of Colorado, Boulder, Colorado 80309, USA.
authors: Owen
authors: O
authors: Puls
authors: Bogolyubov Institute for Theoretical Physics, NAS of Ukraine, Kyiv 03680, Ukraine.|Department of Mathematics, University of Akron, Akron, Ohio 44325, USA.
authors: Oleh M
authors: OM
authors: Tovkach
authors: Institute of Physics, NAS of Ukraine, Kyiv 03650, Ukraine.
authors: Stanislav B
authors: SB
authors: Chernyshuk
authors: Department of Physics and Soft Materials Research Center, University of Colorado, Boulder, Colorado 80309, USA.|Department of Electrical, Computer, and Energy Engineering, Materials Science and Engineering Program, University of Colorado, Boulder, Colorado 80309, USA.|Renewable and Sustainable Energy Institute, National Renewable Energy Laboratory and University of Colorado, Boulder, Colorado 80309, USA.
authors: Ivan I
authors: II
authors: Smalyukh