We use Inline Digital Holography to measure the diffusion coefficient of spherical colloids with a 1.06mm radius in the bulk of a liquid. We obtain a diffusion coefficient of 0.23 +/- 0.03mm2/s...Show moreWe use Inline Digital Holography to measure the diffusion coefficient of spherical colloids with a 1.06mm radius in the bulk of a liquid. We obtain a diffusion coefficient of 0.23 +/- 0.03mm2/s which is in good agreement with Stokes-Einstein theory. We attempt the measurements to active Janus colloid spheres and explore the possibilities and limitations of the technique. We use the Discrete Dipole Approximation to fit the holograms to the Lorenz-Mie theory and report on the viability of the computation. We discuss the minimum necessary requirements for performing a successful fitting and analysis of the motion of Janus colloid spheres, in the bulk of a medium, using inline holographyShow less
An important goal in soft matter physics is to steer microscale self-assembly processes. Here we show linear structures made of colloids and the energy landscape that describes the angular mobility...Show moreAn important goal in soft matter physics is to steer microscale self-assembly processes. Here we show linear structures made of colloids and the energy landscape that describes the angular mobility. It was done by functionalizing isotropic and anisotropic colloids with a lipid bilayer and insert DNA linkers that have a specific binding group. The DNA linkers are fully mobile along the particle surface and colloids functionalized with DNA linkers are able to form flexible polymers. Specifically, we looked at polymers consisting of four monomers: tetramers and found very mobile clusters that had an averaged joint mobility of 154 +- 3 deg2/s. In the energy landscape that we experimentally and theoretically found, we can conclude the preferred angles are 180/180 degrees. For polymers made of two dumbbell particles we found a mobile bilayer, but no mobile clusters were found. Our tunable tetramers could be the design for a model of controlled self-assembly in even larger structures and define the cluster properties.Show less
We seek to study the in uence of substrate geometry on di usion of substrate attached particles by building a model system in which colloidal particles are attached to a supported lipid bilayer on...Show moreWe seek to study the in uence of substrate geometry on di usion of substrate attached particles by building a model system in which colloidal particles are attached to a supported lipid bilayer on TPA suitable material. We test a variety of lipid compositions and polyelectrolyte cushioning with respect to lipid mobility. Our experimental e orts show that DOPC/DOPE-PEG2000 uid lipid bilayers on glass and ORMOCER can be created. DNA linkers with cholesterol anchors are adsorbed in this bilayer and polystyrene colloids coated with complementary DNA linkers are coupled to the linkers in the bilayer. We show that the colloids di use in a two dimensional fashion on a glass substrate.Show less
