Abstract
We study the compression of depletion gels under the influence of a gravitational stress by monitoring the time evolution of the gel interface and the local volume fraction, \( \phi\), inside the gel. We find \( \phi\) is not constant throughout the gel. Instead, there is a volume fraction gradient that develops and grows along the gel height as the compression process proceeds. Our results are correctly described by a non-linear poroelastic model that explicitly incorporates the \( \phi\) -dependence of the gravitational, elastic and viscous stresses acting on the gel.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
G. Foffi, C.D. Michele, F. Sciortino, P. Tartaglia, Phys. Rev. Lett. 94, 078301 (2005).
N.A.M. Verhaegh, D. Asnaghi, H.N.W. Lerkkerkerker, M. Giglio, L. Cipelletti, Physica A 242, 104 (1997).
S. Asakura, F. Oosawa, J. Chem. Phys. 22, 1255 (1954).
S. Manley, J.M. Skotheim, L. Mahadevan, D.A. Weitz, Phys. Rev. Lett. 94, 218302 (2005).
C. Kim, Y. Liu, A. Kühnle, S. Hess, S. Viereck, T. Danner, L. Mahadevan, D.A. Weitz, Phys. Rev. Lett. 99, 028303 (2007).
L. Antl, J. Goodwin, R. Hill, S. Owens, S. Papworth, J.A. Waters, Colloid Surf. 17, 67 (1986).
P. Greenspan, E. Mayer, S. Fowler, J. Cell. Biol. 100, 965 (1985).
P.J. Lu, J.C. Conrad, H.M. Wyss, A.B. Schofield, D.A. Weitz, Phys. Rev. Lett. 96, 028306 (2006).
A. Yethiraj, A. Blaaderen, Nature (London) 421, 513 (2003).
M.F. Hsu, E.R. Dufresne, D.A. Weitz, Langmuir 21, 4881 (2005).
D.R. Lide, 79th CRC Handbook of Chemistry and Physics (CRC Press, Boca Raton, 1999).
J. Brandup, Polymer Handbook (Wiley, New York, 1998).
We have performed similar experiments with polystyrene particles in the presence of non-adsorbing polymer. In this case, the system does not cream but rather sediments along the gravitational direction
R. Buscall, Colloid Surf. 5, 269 (1982).
The volume fraction for gelation is taken from lu, which contains the phase diagram for our experimental system.
The length scale of a pixel in one of our images is 10 m. We thus expect that the structure of the colloidal suspension should not greatly affect the transmission through the sample. We also assume that contributions arising from the scattering from other parts of the cell are negligible compared to the transmission dhont.
J.K.G. Dhont, An Introduction to the Dynamics of Colloids (Elsevier, Amsterdam, 1996).
H. Darcy, Les fontaines publiques de la ville de Dijon (Dalmont, Paris, 1856).
A.D. Dinsmore, V. Prasad, I. Wong, D.A. Weitz, Phys. Rev. Lett. 96, 185502 (2007).
In the initial compression stages, the gel does not change appreciably its volume fraction. As a result, the elastic stress gradient in equation (balance) can be neglected. The initial stages are thus determined by the balance between the gravitational and frictional stress gradients. This is used to determine the initial permeability of the gel from the slope of the interface evolution with time. See manley for further details.
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Liétor-Santos, J.J., Kim, C., Lu, P.J. et al. Gravitational compression of colloidal gels. Eur. Phys. J. E 28, 159–164 (2009). https://doi.org/10.1140/epje/i2008-10390-7
Received:
Revised:
Published:
Issue Date:
DOI: https://doi.org/10.1140/epje/i2008-10390-7