Equilibrium cluster formation in concentrated protein solutions and colloids
- A. Stradner, H. Sedgwick, F. Cardinaux, W. Poon, S. Egelhaaf, P. Schurtenberger
- Materials Science, ChemistryNature
- 25 November 2004
It is demonstrated that in both model systems, a combination of short-range attraction and long-range repulsion results in the formation of small equilibrium clusters, which is relevant for nucleation processes during protein crystallization, protein or DNA self-assembly.
Flagellated bacterial motility in polymer solutions
- V. Martinez, J. Schwarz-Linek, M. Reufer, L. Wilson, A. Morozov, W. Poon
- BiologyProceedings of the National Academy of Sciences
- 21 November 2014
The current standard model of how bacteria propelled by rotary helical flagella swim through concentrated polymer solutions postulates bacteria-sized pores, allowing them relative easy passage is overturned, and clear evidence for non-Newtonian effects in the highest-molecular-weight PVP solution is found.
Phase Behaviour of Colloid + Polymer Mixtures
A new treatment of the phase behaviour of a colloid + nonadsorbing polymer mixture is described. The calculated phase diagrams show marked polymer partitioning between coexisting phases, an effect…
Molecular segregation observed in a concentrated alcohol–water solution
When a simple alcohol such as methanol or ethanol is mixed with water, the entropy of the system increases far less than expected for an ideal solution of randomly mixed molecules. This well-known…
Ionic effects in self-propelled Pt-coated Janus swimmers.
It is found here that the direction of propulsion can be reversed by addition of an ionic surfactant, and that although adding pH neutral salts reduces the propulsion speed, adding the strong base NaOH has little effect.
Multiple Glassy States in a Simple Model System
Experiments, theory, and simulation were used to study glass formation in a simple model system composed of hard spheres with short-range attraction (“sticky hard spheres”) and revealed a reentrant glass transition line.
Yielding behavior of repulsion- and attraction-dominated colloidal glasses
- K. N. Pham, G. Petekidis, D. Vlassopoulos, S. Egelhaaf, W. Poon, P. Pusey
- Materials Science
- 7 March 2008
We report a number of experiments, mainly rheological measurements, examining the yielding behavior of colloidal glasses with hard-sphere interaction plus a short-range attraction. The system is a…
Three-dimensional imaging of colloidal glasses under steady shear.
The possible role of large scale shear localization and other mechanisms in generating the structural relaxation of particles in a yielded hard-sphere colloidal glass under steady shear are discussed.
On measuring colloidal volume fractions
Hard-sphere colloids are popular as models for testing fundamental theories in condensed matter and statistical physics, from crystal nucleation to the glass transition. A single parameter, the…
Phase separation and rotor self-assembly in active particle suspensions
- J. Schwarz-Linek, C. Valeriani, W. Poon
- ChemistryProceedings of the National Academy of Sciences
- 5 March 2012
The authors' simulations suggest that both the suppression of phase separation and the self-assembly of rotors are generic features of aggregating swimmers and should therefore occur in a variety of biological and synthetic active particle systems.