LINEAR VISCOELASTICITY IN LIPID BILAYERS OF VESICLES

In two preceding articles the complex shear viscosity of a dispersion of vesicles has been determined and from an observed macroscopic relax ation time that pertains to deformation of vesicles a value of the sta tic shear modulus has been calculated with the use of the Oldroyd mode l. In the present paper this model has been extended by incorporating in the shear behavior of the lipid bilayer a linear viscoelastic behav ior with one relaxation time in order to be able to relate the macrosc opic relaxation time to a dynamic shear modulus instead of a static sh ear modulus. The latter is believed not to exist. With the extended Ol droyd model the experimental results can be interpreted, This leads to a value of the dynamic shear modulus.