Polystyrene static light scattering

Now, let us look at Fig. 13. Here, the static structure factor of a three-dimensional homogeneous suspension of polystyrene spheres of diameter 94 nm is shown. The particles volume fraction is 0 = 2.0 x 10 4. Experimental data from static light scattering (closed circles) are compared with computer simulation (Monte Carlo) results (symbol x) and theoretical predictions (lines) obtained from the Ornstein-Zernike equation and different closure relations. The computer simulations and the theoretical calculations where carried out assuming that the interaction between the... 

This communication which is a continuation and a development of our previous study [5] is devoted to closer examination of the polystyrene particles formation process in supercritical n-butane induced by small pressure variation. This study was carried out using both DLS (dynamic light scattering) and SLS (static light scattering), which permitted us to investigate the fast (10-30 sec) process of appearance and the aggregation of the particles, to determine their mean radius (R ) and concentration (N). 

Fig. 5. Correlation length, scaled on Rt, as a function of reduced concentration X c/c as measured through static light-scattering by Wiltzius et al. (1983). Symbols denote various molecular weight polystyrenes in toluene and methyl ethyl ketone at 25°C.

From these data determine the second virial coefficient and the theta temperature of poly(a-methyl styrene) in cyclohexane, knowing that K = K hl AhlAcf, where K = 18.17 mol cm , the refractive index increment (d /dc) is 0.199 ml gr, and the temperature dependence of the refractive index is expressed by = -0.0005327 x T (°C) + 1.446. Static light-scattering measurements were carried out by Zimm (1948b) on polystyrene in butanone at 340 K at two concentrations. 

Kent, et al. [107] report Rg and Dp of 233 and 930 kDa polystyrenes in 7, 66, 70, 840, and 1300 kDa polymethylmethacrylates in ethyl benzoate (for static light scattering) cind toluene (for QELSS). Except for the 66 kDa PMMA, M /Mp <1.10. D of the polystyrene was mecisured cis a function of polystyrene concentration, thereby obtaining both Dp and the initial linear slope of D against polystyrene concentration. Figure 24d shows Rg of the 930 kDa pol5rstyrene as a function of PMMA concentration. Rg follows... 

GPC data and molecular weight values are relative to polystyrene standards. Althou in this case gpc provides only molecular weight estimates, absolute determinations of ilfw by static light scattering for several polymers have indicated that gpc underestimates the real values by a factor of 2 (144). 

The molecular weights determined by static light scattering were in remarkable agreement with GPC measurements analyzed by using a polystyrene calibration. This is a fortunate result, since the molecular weight of poly(3-alkylthiophene) was usually determined by GPC. 

Figure 4.16. Scaling plot for the correlation length evaluated in static light-scattering measurements for solutions of polystyrene in toluene and methyl ethyl ketone. The reduced correlation length i/Rgo is plotted as a function of l6/9)A2Mc in a double logarithmic scale. The dashed line has a slope of —3/4. (From Ref. 48.)...

WAK Wakker, A., Van Dijk, F., and Van Dijk, M.A., Phase behavior of polystyrene in methyl acetate A static light scattering sta y,Macromolecules, 26, 5088, 1993. 

Fig. 1.5 Deviation of the molar mass values for hypetbranched poly (etheramide) determined by different SEC-interpretation methods square) SEC-RI detection tmd polyethylene oxide standard (cycle) SEC-RI detection and polystyrene standard (triangle) of-line SEC-viscosity detection and universal calibration (inverted triangle) SEC-MALLS (static light-scattering detection) [62]...

Nordmeier and Dauwe [282] reported static light scattering experiments on polystyrene sulphonate at 0.005 m c 2 m and analyzed the data by a worm-like chain model. The resulting total apparent persistence length is compared to the data of [210] in Fig. 18. The agreement is quite poor, and the data of [282] do not follow at all the scaling-law (solid line in Fig. 18). 

Kuhn, et al., exploited these results to study polystyrene polymethylmethacrylate benzene(21-23). Polymethylmethacrylate and benzene are isorefractive. The authors used static light scattering to determine the second virial coefficient A2, the... 

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,... 

Figm 8 Experimental results of static light scattering for dilute and concentrated turbid suspensions of spherical particles (polystyrene latex with average radius 274 nm). (a) Normalized scattering intensity measured by an ordinary LLS instrument for a dilute solution (hollow circles)... 

In addition to the intrinsic lack of stationarity, many of the fluctuations in the glass relax so slowly that they appear to be static sources of light scattering on the time scale of the data collection. These static contributions will introduce a heterodyne component into the observed relaxation function. If the fraction of the light which is quasi-static exceeds 90%, then the observed relaxation function can be interpreted as a heterodyne case and an analysis can be carried out. However, it is not clear that this limit is ever reached in practice. Only 60% of the light was slowly relaxing at all in polystyrene. If at least 90% of the slowly relaxing part becomes quasi-static the heterodyne case will still apply to the observed part of the relaxation function. For PMMA and PEMA this is unlikely to be the case at any temperature near Tg. 

FIG. 12 Pattern of light scattered from a single layer of colloidal particles in the disordered phase. The particles are polystyrene spheres, of diameter 2 /glass plates. Except for the contribution of the form factor P(k), which depends on the scattering angle, and normalization and geometrical factors, this picture shows directly the static structure factor of the system. 

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