Osmotic bulk modulus

The osmotic bulk modulus K = C 8 7T/8 C was measured by static light-scattering it was found that K is mass-independent and increases with concentration following ... 

In dilute (C 0) and semidilute solutions, the osmotic bulk modulus (or osmotic pressure) is proportional to the number of non-interacting... 

It is important to note that at the 0-temperature the shear elastic modulus G does not have the same concentration-dependence as the osmotic bulk modulus /f, but both quantities are of the same order of magnitude ... 

Increasing the quality of solvent the elastic modulus decreases slightly whereas the osmotic bulk modulus increases strongly. Typically at C = 4 X 10 2g/cm3 4,20,7,8... 

Such a dramatic change is also reflected in the time-dependence of the dynamical structure factor. The line shape, non-exponential in the gel regime at the 0-temperature, becomes more and more exponential as we increase the temperature from 35°C to 65 C. A single exponential line is observed in polystyrene-benzene system.This is due to the fact that the relative intensity I /Ig of the slow mode (x ) to the fast mode (x ) is proportional to the ratio of the elastic modulus to the osmotic bulk modulus... 

All the thermodynamic and hydrodynamic quantities, which are sensitive to 5, such as osmotic bulk modulus, sedimentation coefficient, and the osmotic diffusion coefficient obey the scaling law in C/C. ... 

Alexander S, Chaikin P M, Grant P, Morales G J, Pincus P and Hone D 1984 Charge renormalisation, osmotic pressure, and bulk modulus of colloidal crystals theory J. Chem. Phys. 80 5776-81... 

S. Alexander, P. M. Chaikin, P. Grant, G. J. Morales, and P. Pincus, /. Chem. Phys., 80, 5776 (1984). Charge Renormalization, Osmotic Pressure, and Bulk Modulus of Colloidal Crystals Theory. 

As usual, the osmotic diffusion coefficient is linked to the bulk osmotic modulus and to the effective mobility per monomer p = p x K/C. The quantity p can be measured through the sedimentation coefficient S = p(1- vp). Comb ing the experimental results for K and S, we obtain >c = 1.13 X 10"° X in agreement with the result presented above. This result confirms that the hydrodynamic screening length is proportional to that of the concentration fluctuations. Actually the scaling law is well verified (see Fig. 6) where is the diffusion coefficient of the isolated polymer chain, is only a function of CIC, ... 

The concentration dependence of the bulk osmotic modulus K -- C ) implies that Mg increases as C. Within the experimental precision, longitudinal and shear elastic moduli are proportional M /G = 6.5. 

What is meant by "soft condensed matter " In the context of this NATO Advanced Study Institute, soft systems are those where the relevant interactions are weak and thermal fluctuations play an important role. However, this is not a sufficiently sharp definition because all materials that have higher order or weakly first order phase transitions, e.g, magnetic materials, superconductors, etc., have this property. I believe that "softness," in addition, implies a relatively high bulk or osmotic compressibility. For a system with a transition temperature, Tc, the elastic modulus, G, scales as... 

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