Jump to main content
Jump to site search
Access to RSC content Close the message box

Continue to access RSC content when you are not at your institution. Follow our step-by-step guide.


Issue 26, 2012
Previous Article Next Article

A qualitative confocal microscopy study on a range of colloidal processes by simulating microgravity conditions through slow rotations

Author affiliations

Abstract

We report qualitatively on the differences between colloidal systems left to evolve in the Earth's gravitational field and the same systems for which a slow continuous rotation averaged out the effects of particle sedimentation on a distance scale small compared to the particle size. Several systems of micron-sized colloidal particles were studied: a hard sphere fluid, colloids interacting via long-range electrostatic repulsion above the freezing volume fraction, an oppositely charged colloidal system close to either gelation and/or crystallization, colloids with a competing short-range depletion attraction and a long-range electrostatic repulsion, colloidal dipolar chains, and colloidal gold platelets under conditions where they formed stacks. Important differences in structure formation were observed between the experiments where the particles were allowed to sediment and those where sedimentation was averaged out. For instance, in the case of colloids interacting via long-range electrostatic repulsion, an unusual sequence of dilute-fluid–dilute-crystal–dense-fluid–dense-crystal phases was observed throughout the suspension under the effect of gravity. This was related to the volume fraction dependence of the colloidal interactions, whereas the system stayed homogeneously crystallized with rotation. For the oppositely charged colloids, a gel-like structure was found to collapse under the influence of gravity with a few crystalline layers grown on top of the sediment, whereas when the colloidal sedimentation was averaged out, the gel completely transformed into crystallites that were oriented randomly throughout the sample. Rotational averaging out of gravitational sedimentation is an effective and cheap way to estimate the importance of gravity for colloidal self-assembly processes.

Graphical abstract: A qualitative confocal microscopy study on a range of colloidal processes by simulating microgravity conditions through slow rotations

Back to tab navigation

Article information


Submitted
18 Nov 2011
Accepted
30 Mar 2012
First published
28 May 2012

Soft Matter, 2012,8, 6979-6990
Article type
Paper

A qualitative confocal microscopy study on a range of colloidal processes by simulating microgravity conditions through slow rotations

D. El Masri, T. Vissers, S. Badaire, J. C. P. Stiefelhagen, H. R. Vutukuri, P. Helfferich, T. H. Zhang, W. K. Kegel, A. Imhof and A. van Blaaderen, Soft Matter, 2012, 8, 6979
DOI: 10.1039/C2SM07217C

Social activity

Search articles by author

Spotlight

Advertisements