T. F. Mohry, A. Maciołek, S. Dietrich
We consider an ensemble of spherical colloidal particles immersed in a
near-critical solvent such as a binary liquid mixture close to its critical
demixing point. The emerging long-ranged fluctuations of the corresponding
order parameter of the solvent drive the divergence of the correlation length.
Spatial confinements of these critical fluctuations by colloidal solute
particles, acting as cavities in the fluctuating medium, restrict and modify
the fluctuation spectrum in a way which depends on their relative
configuration. This results in effective, so-called critical Casimir forces
(CCFs) acting on the confining surfaces. Using the available knowledge about
CCFs we study the structure and stability of such colloidal suspensions by
employing an approach in terms of effective, one-component colloidal systems.
Applying the approximation of pairwise additive CCFs we calculate the radial
distribution function of the colloids, which is experimentally accessible. We
analyze colloidal aggregation due to CCFs and thus allude to previous
experimental studies which are still under debate
View original:
http://arxiv.org/abs/1201.5547
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