Study of a colloidal sphere near flat walls using oscillating optical tweezers

We study the dynamics of a micron-sized colloidal sphere in two cases; one is for a particle near a single flat wall and the other is for a particle confined between two parallel flat walls. In this geometry, the force felt by a moving particle is quite different from that of a moving particle in unbounded space. Even though the presence of wall(s) complicates the flow field surrounding the colloidal sphere, the dynamics of a colloidal sphere near flat walls provides a model system with which to understand the phenomenon of more complex systems whose boundaries can be modeled as effective walls.[1] In this work, hydrodynamic interactions of colloidal sphere with nearby plat wall(s) are studied by using oscillating optical tweezers and compared with known theories and other experimental results using different techniques.

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