Polystyrene osmotic compressibility

Fig. 15.29. Osmotic compressibility of polystyrene solutions, obtained by neutron and X-ray scattering, as a function of overlap ratio (from Wiltzius et al.2A). Samples identical to those of Fig. 15.29.

Fig. 16.12. The osmotic compressibility plotted against the overlap ratio at temperature Tf (from Stepanek, Perzynski, Delsanti, and Adam19). Polystyrene in cyclohexane Values measured by light scattering...

Stepanek et al. (1984) applied light scattering to measure the reduced osmotic compressibility (see Equation 83) in the 0 region and while going through the crossover (by temperature, c = const) in polystyrene solutions in cyclohexane they established that in the concentration rruige 2 < c/cj < 11 at T = 0... 

The presence of a primary maximum in the potential of Figure 1 should imply an inflexion in the osmotic pressure versus volume fraction plot indicative of coagulation. The effect is indeed found in the computer simulations and to differing extents in the osmotic compression experiments. Meijer et al. have used the cell model to predict critical coagulation pressures to compare with their experimental results on the centrifugation of monodisperse polystyrene latices (diameter 0.5 jum). In the cell theory, the osmotic pressure is given by... 

Figure 4.11. Reduced osmotic compressibility, M/NpJ(. T) d l/dcyj plotted as a function of (16/9)A2Mc in a double logarithmic scale, obtained in the static Ught-scattering experiments for solutions of polystyrene of various molecular weights in toluene and methyl ethyl ketone. (From Ref. 48.)...

Figure 7.12 Mesoscale osmotic compressibility measured by intensity of light scattering ///r where f is a reference intensity versus T— at two different wave numbers in polystyrene ( Zp = 2.10 )-h cyclohexane solution " The scattering angles 150° and 30° corresponds to the instrumental length scales =L 36nm and about 500nm, respectively. —, the scaling predictions in accordance with eq 7.95 ---------------------, the...

HAM Hamano, K., Kuwahara, N., and Kaneko, M., Scaled functions of osmotic compressibility and correlation length of polystyrene in diethyl malonate, Phys. Rev. A, 20, 1135, 1979. 

B. Chu and T. Nose, "Static and Dynamical Properties of Polystyrene in trans-Decalin. 4. Osmotic Compressibility, Characteristic Lengths and Internal and Pseudogel Motions in the Semidilute Regime, Macromolecules. Ji, 122-132 (1980). 

A systematic study of Dm (c) and related quantities was made by Koch, etal. 9) using polystyrene dioxane solutions. The solution inverse osmotic compressibility dfl/dc was obtained with static light scattering. A generalized Stokes-Einstein equation,... 

Light scattering experiments were also performed in semi-dilute solutions of linear polystyrenes in benzeneThe osmotic compressibility of these systems was determined from the extrapolation of the scattered intensity to q = 0, in Fig. 9, which shows the plot of C o against concentration it can be seen that the data are also in good agreement with the theoretical prediction... 

The extremely low friction achieved on PLL(20)-g[2.9]-PEG(5) films in SFA experiments is not a unique property of this specific copolymer but has also been observed for other grafted poly(ethylene glycol) films as well as for other polymer-brush systems in a good solvent, such as grafted polystyrene in toluene. The osmotic pressure, which leads to strong repulsive forces as the polymer brushes are compressed, effectively prevents the direct contact of the solid surfaces. At comparable solid surface separations, thin films of water or aqueous salt solutions have been shown to retain a shear fluidity characteristic of the bulk liquid. In a control experiment, this was also observed in 10 mM HEPES buffer solution (data not shown). 

---