**Structure and thermodynamics of colloids clothed **

**by end-grafted polymer chains **

**in high-molecular-weight solvent**

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**M. Yassine, M. Benzouine, M. Benhamou***

*Laboratoire de Physique des Polymères et Phénomènes Critiques*

*Faculté des Sciences Ben M’sik, P.B. 7955, Sidi Othman, Casablanca, Morocco *

** Corresponding author. **E-mail: **benhamou_mabrouk@yahoo.fr*

*Received: 24 December 2006; revised version accepted: 17 July 2007*

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**Abstract **

We consider an assembly of colloids clothed each by f end-grafted long polymer chains of common polymerization degree N. We assume that these clothed colloids are immersed in a high-molecular-weight solvent, made of polymer chains of the same polymerization degree . First, we show that the effective potential between two clothed colloids is *logarithmic*, for distances smaller than their corona radius . For higher distances, that is above , the potential fails *exponentially*. Second, we investigate the structure and thermodynamics of the clothed colloids, using the *integral equation method* with the *hybridized-mean spherical approximation*. The numerical resolution of this integral equation enables us to determine the associated structure factor, as a function of the wave-vector, the particle density and the polymerization degree P. The relation between thermodynamics and structure allows the computation of three physical quantities, which are the isotherm compressibility, pressure and internal energy. Finally, a comparison with the results relative to clothed particles trapped in low-molecular-weight solvents is made.

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