Applications for photonic crystals and metamaterials put stringent requirements on the characteristics of advanced optical materials, demanding tunability, high Q factors, applicability in visible range, and large-scale self-assembly. Exploiting the interplay between structural and optical properties, colloidal lattices embedded in liquid crystals (LCs) are promising candidates for such materia...

The dynamics of a glass-forming material slow greatly near the glass transition, and molecular motion becomes inhibited. We use confocal microscopy to investigate the motion of colloidal particles near the colloidal glass transition. As the concentration in a dense colloidal suspension is increased, particles become confined in transient cages formed by their neighbors. This prevents them from ...

We report the direct measurement of thermodynamic properties of colloidal hard spheres by optical microscopy. By using confocal microscopy, we obtain three-dimensional snapshots of a colloidal hard-sphere suspension over a wide range of densities. From these snapshots, the available volume to insert an additional sphere and the surface area of that volume are determined, which are directly rela...

In the emerging issue of increased multi-resistant properties in foodborne pathogens, silver nano particles are being used increasingly as antimicrobial agents. Thus, the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of Nano Colloidal Silver towards food-borne pathogens such as Escherichia coli O157:H7, Listeria monocytogenes, Salmonella enterica Serovar Ty...

Colloidal suspensions have proven to be excellent model systems for the study of condensed matter and its phase behavior [1]. Many of the properties of colloidal suspensions can be investigated with a systematic variation of the characteristics of the systems and, in addition, the energy, length and time scales associated with them allow for experimental probing of otherwise inaccessible regime...

Knowledge of the structure and interactions of mixed polymer/surfactant colloidal systems is essential for simultaneously controlling the stability and rheological properties of colloidal dispersions such as emulsions and lubricating oils [1, 2]. The surfactant and polymer together provide stability against coagulation and control the viscosity of the ̄uid, the practical aim being to produce hig...

We use confocal microscopy to directly visualize the dynamics of aging colloidal glasses. We prepare a colloidal suspension at high density, a simple model system which shares many properties with other glasses, and initiate experiments by stirring the sample. We follow the motion of several thousand colloidal particles after the stirring and observe that their motion significantly slows as the...

We describe a novel method of tracking the rotational motion of clusters of colloidal particles. Our method utilizes rigid body transformations to determine the rotations of a cluster and extends conventional proven particle tracking techniques in a simple way, thus facilitating the study of rotational dynamics in systems containing or composed of colloidal clusters. We test our method by measu...