Abstract
The position of a colloidal particle trapped in an external field thermally fluctuates at equilibrium. As is well known, the ambient fluid is not a simple heat bath and the particle mass appears to increase, which influences the mean square velocity of the particle. In this study, we suppose that the particle is surrounded by a binary fluid mixture in the homogeneous phase near, but not too close to, the critical point. Usually, one component is preferably attracted by the particle surface, and the resultant adsorption layer becomes significant because of the near-criticality. When the particle fluctuates in this situation, its mean square displacement should also be influenced by the ambient fluid because the adsorption layer does not follow the particle motion totally. We calculate the influence in a simple case, where a rigid spherical particle fluctuates with a small amplitude and its surface attracts one component weakly. We utilize the hydrodynamics in the limit of no dissipation to examine the contribution from the ambient mixture to the equal-time correlation. According to our result, the mean square displacement is reduced by an additional stress, including osmotic pressure.
| Original language | English |
|---|---|
| Article number | 044401 |
| Journal | Journal of the Physical Society of Japan |
| Volume | 85 |
| Issue number | 4 |
| DOIs | |
| Publication status | Published - 2016 Apr 15 |
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ASJC Scopus subject areas
- Physics and Astronomy(all)
Cite this
Fluctuation amplitude of a trapped rigid sphere immersed in a near-critical binary fluid mixture within the regime of the Gaussian model. / Fujitani, Youhei.
In: Journal of the Physical Society of Japan, Vol. 85, No. 4, 044401, 15.04.2016.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Fluctuation amplitude of a trapped rigid sphere immersed in a near-critical binary fluid mixture within the regime of the Gaussian model
AU - Fujitani, Youhei
PY - 2016/4/15
Y1 - 2016/4/15
N2 - The position of a colloidal particle trapped in an external field thermally fluctuates at equilibrium. As is well known, the ambient fluid is not a simple heat bath and the particle mass appears to increase, which influences the mean square velocity of the particle. In this study, we suppose that the particle is surrounded by a binary fluid mixture in the homogeneous phase near, but not too close to, the critical point. Usually, one component is preferably attracted by the particle surface, and the resultant adsorption layer becomes significant because of the near-criticality. When the particle fluctuates in this situation, its mean square displacement should also be influenced by the ambient fluid because the adsorption layer does not follow the particle motion totally. We calculate the influence in a simple case, where a rigid spherical particle fluctuates with a small amplitude and its surface attracts one component weakly. We utilize the hydrodynamics in the limit of no dissipation to examine the contribution from the ambient mixture to the equal-time correlation. According to our result, the mean square displacement is reduced by an additional stress, including osmotic pressure.
AB - The position of a colloidal particle trapped in an external field thermally fluctuates at equilibrium. As is well known, the ambient fluid is not a simple heat bath and the particle mass appears to increase, which influences the mean square velocity of the particle. In this study, we suppose that the particle is surrounded by a binary fluid mixture in the homogeneous phase near, but not too close to, the critical point. Usually, one component is preferably attracted by the particle surface, and the resultant adsorption layer becomes significant because of the near-criticality. When the particle fluctuates in this situation, its mean square displacement should also be influenced by the ambient fluid because the adsorption layer does not follow the particle motion totally. We calculate the influence in a simple case, where a rigid spherical particle fluctuates with a small amplitude and its surface attracts one component weakly. We utilize the hydrodynamics in the limit of no dissipation to examine the contribution from the ambient mixture to the equal-time correlation. According to our result, the mean square displacement is reduced by an additional stress, including osmotic pressure.
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UR - http://www.scopus.com/inward/citedby.url?scp=84962360319&partnerID=8YFLogxK
U2 - 10.7566/JPSJ.85.044401
DO - 10.7566/JPSJ.85.044401
M3 - Article
AN - SCOPUS:84962360319
VL - 85
JO - Journal of the Physical Society of Japan
JF - Journal of the Physical Society of Japan
SN - 0031-9015
IS - 4
M1 - 044401
ER -