Analysis of hydrodynamic interactions of single particles by the use of optical tweezers.

PI: Krzysztof Zembrzycki
Funding agency: National Science Centre (NCN)
Programme: Preludium 10
Grant period: 1st September 2016 – 31st August 2019

The aim of the project is to elucidate the mechanisms of interactions of single colloidal micro and nanoparticles, suspended in a fluid, using Optical Tweezers combined with an Atomic Force Microscope.
Research will concentrate on interactions of individual particles suspended in liquids by measuring their Brownian motion in the Optical Tweezers, forces between two particles, forces between particle and the wall, ionic and steric effects. In the experiments, different ionic concentrations in the fluid will be used to fully evaluate the effects of their concentrations on Brownian motion of particles confined in the optical trap and to measure the interaction forces between a single particle and a fixed surface. An ionic double layer arises on the surface of the particle due to the particles inner charge. As a result, the effective hydrodynamic radius of the bead may be significantly different from its geometrical one and will depend on the concentration and type of ions in the fluid. This in turn will affect the diffusion of these particles and may compromise the results given by test and lab equipment that relay on measuring the diffusion of colloids in liquids.

Pierini Research Group Sylwia Pawlowska NCN Preludium Nanoparticles Hydrodynamic Radius Micro Microfluidics Nano Fluidics DLVO Double Layer Mobility Fluid Interactions Brownian Motion