Picture of athlete cycling

Open Access research with a real impact on health...

The Strathprints institutional repository is a digital archive of University of Strathclyde's Open Access research outputs. Strathprints provides access to thousands of Open Access research papers by Strathclyde researchers, including by researchers from the Physical Activity for Health Group based within the School of Psychological Sciences & Health. Research here seeks to better understand how and why physical activity improves health, gain a better understanding of the amount, intensity, and type of physical activity needed for health benefits, and evaluate the effect of interventions to promote physical activity.

Explore open research content by Physical Activity for Health...

The depletion attraction between pairs of colloid particles in polymer solution

Striolo, Alberto and Colina, Coray M. and Gubbins, Keith E. and Elvassore, Nicola and Lue, L. (2004) The depletion attraction between pairs of colloid particles in polymer solution. Molecular Simulation, 30 (7). pp. 437-449. ISSN 0892-7022

Full text not available in this repository. Request a copy from the Strathclyde author

Abstract

NVT Monte Carlo simulations were used to assess the effective interaction between pairs of colloid particles dissolved in non-adsorbing polymer solutions. The polymers were represented as freely-jointed-hard-sphere chains composed of 10, 20, or 30 segments. The size of the interacting colloid particles was similar to or smaller than the radius of gyration of the polymers. Results show a short-range colloid-colloid depletion attraction. At low polymer concentration, this attraction slowly decays to zero at increasing separations. At higher polymer concentration, the depletion attraction is coupled to a mid-range repulsion, especially for solutions of short, stiff polymers. From the simulated forces, osmotic second virial coefficients were computed for colloids as a function of polymer concentration. The calculated osmotic second virial coefficients exhibit a non-monotonic dependence on polymer concentration, in qualitative agreement with experimental results. The simulated colloid-colloid potentials of mean force were used, within a perturbation theory, to calculate fluid-fluid and fluid-solid coexistence curves. The colloids are treated as a pseudo one-component system, and the polymers in solution are considered only through the effective pair potential between the dissolved colloids. When long flexible polymers are dissolved in solution, the phase diagram for small colloid particles shows a fluid-fluid coexistence curve at low colloid packing fraction, and a fluid-solid coexistence curve at higher packing fraction. As the size of the colloid particles increases, the molecular weight of the polymer decreases, or the polymer concentration in solution increases, the fluid-fluid coexistence curve becomes metastable with respect to the fluid-solid coexistence curve.