Mohan Srinivasarao

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The iridescent metallic green beetle, Chrysina gloriosa, which selectively reflects left circularly polarized light, possesses an exoskeleton decorated by hexagonal cells (approximately 10 microm) that coexist with pentagons and heptagons. The fraction of hexagons decreases with an increase in curvature. In bright field microscopy, each cell contains a(More)
The color of colloidal dispersions of gold particles in a fluid, typically water, varies from red to blue, depending upon the shape and size of particles. The color and optical properties of gold nanoparticles originate from localized surface plasmons, and are sensitive to their local dielectric environment. Unlike nanospheres, the optical properties,(More)
We report the formation of a three-dimensionally ordered array of air bubbles of monodisperse pore size in a polymer film through a templating mechanism based on thermocapillary convection. Dilute solutions of a simple, coil-like polymer in a volatile solvent are cast on a glass slide in the presence of moist air flowing across the surface. Evaporative(More)
We demonstrate the use of centrifugation for efficient separation of colloidal gold nanorods from a mixture of nanorods and nanospheres. We elucidate the hydrodynamic behavior of nanoparticles of various shapes and illustrate that the shape-dependent drag causes particles to have shape-dependent sedimentation behavior. During centrifugation, nanoparticles(More)
The presumed ground state of a nematic fluid confined in a cylindrical geometry with planar anchoring corresponds to that of an axial configuration, wherein the director, free of deformations, is along the long axis of the cylinder. However, upon confinement of lyotropic chromonic liquid crystals in cylindrical geometries, here we uncover a surprising(More)
An azide-substituted poly(para-phenyleneethynylene) (PPE) 4 was prepared by the Heck-Cassar-Sonogashira-Hagihara method. Thin films of 4 form self-assembled bubble arrays from carbon disulfide solution utilizing the breath figure method. The as-formed porous films of 4 are soluble in common solvents, and the air bubbles are interconnected. Upon heating to(More)
Dew or breath figures is a disordered pattern formed by polydisperse water drops that form when a cold surface comes in contact with breath or moist air. Unexpectedly, self-assembled arrays of non-coalescent monodisperse water drops form when dilute solutions of polymers in volatile organic solvents are exposed to moist air. After solvent evaporation is(More)
Lyotropic chromonic liquid crystals are distinct from thermotropic nematics from a fundamental standpoint as the structure of the aggregating columns is a function of both the temperature and concentration. We report on the thermal evolution of orientational order parameters, both the second (=scalar) (⟨P200⟩ (=S)) and fourth (⟨P400⟩) order, of sunset(More)