Experimental study of critical casimir forces on microparticles in critical binary liquid mixtures
Author(s)
Advisor
Volpe, GiovanniDate
2014Publisher
Bilkent University
Language
English
Type
ThesisItem Usage Stats
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Abstract
Long-ranged forces between mesoscopic objects emerge when a fluctuating
field is confined. Analogously to the well known quantum-electro-dynamical
(QED) Casimir forces, emerging between conducting objects due to the confinement
of the vacuum electromagnetic fluctuations, critical Casimir forces emerge
between objects due to confinement of the fluid density fluctuations. Here, we
studied experimentally several novel aspects and applications of critical Casimir
fluctuations in a critical mixture of walter-2,6-lutidine, which are a promising
candidate to harness forces and interactions at mesoscopic and nanoscopic lengthscales
and promise to deliver results of both fundamental and applied interest.
In particular, we studied the critical Casimir forces between multiple objects
and multiple-body effects. We first extended the experimental study of critical
Casimir forces in configurations different from the particle-wall system[1]. The
forces acting between two particles in far from any surface and the third particle
effect were explored. Then we employed multiple reconfigurable holographic
optical tweezers (HOTs) which permit to optically trap several colloids and used
a technique known as ”digital video microscopy” (DVM) to track the particles’
trajectories and the forces acting on the particles. We studied the critical Casimir
force arising between two particles as a function of their distance and investigated
how this is affected by the presence of a third neighboring particle.
Keywords
Critical FluctuationsCritical Casimir Forces
Quantum-electrodynamical Casimir Forces
Force Measurement
Optical Tweezers
Photonic Force Microscopy
Digital Video Microscopy