I. Joudar, K. El Hasnaoui, H. KaïdiH. Ridouane , H. Qamar, M. Benhamou

We reexamine here the study of the phase separation between phospholipids and anchored polymer chains onto a fluid membrane,under a change of some suitable parameter (temperature). The purpose is to quantify the important effects of the solvent quality and the polydispersity of the grafted chains on the segregation phenomenon. First, we elaborate a theoretical model that allows us the determination of the mixing free energy expression. From the latter, we extract the phase diagram shape in the composition temperature plane. Second, we compute the structure factor and discuss the role of the strong fluctuations of composition near the consolute point. The main conclusion is that, the polymer chains condensation is very sensitive to the solvent quality and polydispersity of the anchored chains.

The aim is the study of the effects of polydispersity and solvent quality on the phase separation between phospholipids and anchored polymer chains by more than one points.

Objective

PerspectivesExtension of the study to charged systemsExtension of the study to charged systems

.

Abstract

Biomembrane with anchored polymer chains

Studied system

Notation:: volume fraction of anchors ;volume fraction of anchors ; : : That of phospholipid moleculesThat of phospholipid molecules..

TT : Absolute temperatureAbsolute temperature..aa :: area of the phospholipids polar-heads ;area of the phospholipids polar-heads ; AA : that of anchorsthat of anchors..

: Areas ratio;Areas ratio;

Good solvents :Good solvents : Theta solvents :Theta solvents :

Segregation parameter :Segregation parameter :

Free energy

Coefficients a and b :Coefficients a and b : They depend on the chemical details and membrane They depend on the chemical details and membrane characteristic characteristic

Phase diagramSpinodal curve :

0,0 0,2 0,4 0,6 0,8 1,00

10

20

30

40

Theta solvents

c

.

0,0 0,2 0,4 0,6 0,8 1,00

10

20

30

40

Good solvents

c

Second International Workshop On Soft Condensed Matter Physics and Biological Systems 28 – 30 April 2010, national Second International Workshop On Soft Condensed Matter Physics and Biological Systems 28 – 30 April 2010, national Fez, MoroccoFez, Morocco

Laboratoire de Physique des Polymères et Phénomènes CritiquesFaculté des Sciences Ben M’sik, P.O. Box 7955, Casablanca, Morocco

Dynamic studyDynamic study

Extension to more than membraneExtension to more than membrane

Structure factorDefinition :Definition :

Small distances behavior :Small distances behavior :

Correlation length :Correlation length :Integration constant :Integration constant :

Partenariats

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