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Equilibrium Structure and Properties of Model Colloidal Suspensions

Author Affiliations

  • 1 Department of Chemistry, Birla Institute of Technology and Science, Pilani – K.K. Birla Goa Campus, Zuarinagar, Goa, INDIA

Res. J. Recent Sci., Volume 2, Issue (ISC-2012), Pages 61-66, February,2 (2013)

Abstract

We report the numerical results on the structure and properties of model colloidal suspensions using the hypernetted-chain (HNC) integral equation due to Allnatt, which has been successfully, applied to asymmetrical electrolyte solutions. We use the primitive model and view our system as highly asymmetrical electrolyte; the colloidal spheres are much larger and more highly charged than the simple ions. The variation of static correlation functions, structure factors and properties, (e.g. excess energies, osmotic coefficients etc.), is reported as a function of size, charge and concentration of colloidal particle. The peak position and the peak height of correlation functions show systematic trends as the asymmetry (in size, charge) increases. The effective one-component potential of the colloid (Veff), calculated by mapping the multicomponent system to an effective one-component colloidal system, is purely repulsive in line with the DLVO potential (with substantial deviations) in most of the cases. However, in some cases (with high asymmetry in charge and size, and at high colloidal concentration), Veff becomes negative.

References

  1. Russel W.B., Condensed-matter physics: Tunable Colloidal Crystals, Nature 421, 490-491 (2003)
  2. Lowen H., Colloidal soft matter under external control, J. Phys.:Condens. Matter 13, R415-R432 (2001)
  3. Brown J.C., Pusey P.N, Goodwin J.W., and Ottewill R.H., Light scattering study of dynamic and time-averaged correlations in dispersions of charged particles J. Phys., A 8, 664 (1975)
  4. Ottewill R.H. and Richardson R.A., Studies of particle-particle interactions using polystyrene lattices and time average light scattering, Colloid Polym. Sci., 260, 708 (1982)
  5. Cebula D.H., Goodwin J.W., Jeffery G.C., Ottewill R.H., Parentich A. and Richaardson R.A., Properties of concentrated polystyrene latex dispersions, Faraday Discuss.Chem. Soc., 76, 37 (1983)
  6. Hartl W., Versrnold H., Wittig U. and Marohn V., Liquid like structure of charged colloidal dispersions in the presence of screening ions, Mol. Phys. 50, 815 (1983)
  7. Belloni L., Colloidal Interactions, J. Phys.: Condens. Matter, 12, R549-R587 (2000)
  8. Likos C.N., Effective interactions in soft condensed matter in physics, Phys. Rep., 348, 267-439 (2001)
  9. Verwey E.J.W. and Overbeek J.T.G., Theory of the Stability of Lyophobic Colloids (Elsevier, Amsterdam, (1948)
  10. Rasaiah J.C., Computations for higher valence electrolytes in the restricted primitive model, J. Chem. Phys., 56, 3071(1972)
  11. Springer J. F., Pokrant M. A., and Stevens F. A., Jr., Integral equation solutions for classical the electron gas, J. Chem. Phys. 58, 4863 (1973)
  12. Ng K.C., Hypernetted chain solutions for the classical one component plasma upto Γ  7000, J. Chem. Phys. 61, 2680 (1974)
  13. Larsen B., Studies in statistical mechanics of Coloumbic systems. III. Numerical solutions of HNC and RHNC equations for the restricted primitive model, J. Chem. Phys., 68, 4511 (1978)
  14. Elkoubi D., Turq P., and Hansen J.P., Application of the HNC approximation to systems of highly charged hard spheres (micelles), Chem. Phys. Lett., 52, 493 (1977)
  15. Rogers F.J., A HNC study of asymmetrically charged hard spheres, J. Chem Phys. 73, 6272 (1980)
  16. Beresford-Smith B. and Chan D. Y. C., Highly asymmetric electrolytes: A model for strongly interacting colloidal systems, Chem. Phys. Lett. 92, 474 (1982)
  17. Belloni L., A hypernetted chain study of highly asymmetrical polyelectrolytes, Chem. Phys., 99, 43 (1985)
  18. Bratko D., Friedman H.L. and Zhong E.C., An integral equation approach to structure and dynamics of ionic colloidal solutions J. Chem. Phys., 85, 377 (1986)
  19. Vladimir Lobaskin and Per Linse, Simulation of an asymmetric electrolyte with charge asymmetry 60:1 using hard-sphere and soft-sphere models, J. Chem. Phys., 111, 4300 (1999)
  20. Allnatt A. R., Integral equations in ionic solution theory, Mol. Phys., 8, 533 (1964)
  21. Rasaiah J.C. and Friedman H.L., Integral Equation Methods in the Computation of Equilibrium Properties of Ionic Solutions, J. Chem. Phys., 48, 2742 (1968)
  22. Das B. and Gupta-Bhaya P., Hpernetted chain calculation of static correlation function of macroions in solution using Allnatt equation, Mol. Phys. 86, 1397 (1995)
  23. Behera R.N. and Gupta-Bhaya P., On attractive interaction of a colloid pair of like charge at infinite dilution, J. Chem. Phys. 126, 044908 (2007)
  24. Khanna T. and Behera R.N., manuscript under preparation.
  25. Kalyuzhnyi Yu. V. and Vlachy V., Integral-equation theory for highly asymmetric electrolyte solutions, Chem. Phys. Lett. 215, 518 (1993)
  26. Kalyuzhnyi Yu. V., Vlachy V., Holovko M. F., Stell G., Multidensity integral equation theory for highly asymmetric electrolyte solutions J.Chem.Phys., 102, 5770 (1995)
  27. Hribar B., Kalyuzhnyi Yu. V. and Vlachy V., Ion-ion correlations in highly asymmetrical electrolytes, Mol. Phys., 87, 1317 (1996)