Polymer solutions small-angle scattering

Sonja Krause, obtained her Ph.D. in Physical Chemistry at the University of California at Berkeley in 1957. She worked as a Senior Physical Chemist at the Rohm and Haas Company until 1964 when she joined the U.S. Peace Corps, teaching for two years in Universities in Nigeria and Ethiopia. She then taught for one year at the University of Southern California in Los Angeles and has been at Rensselaer Polytechnic Institute, presently as Professor of Physical Chemistry, since 1967. Her research interests include polymer-polymer miscibility, phase-separated polymer systems, small-angle scattering, and transient electric birefringence of macromolecules in solution. 

Plestil J, Ostanevich YM, Bezzabotonov VY, Hlavata D, Labsky J. Small-angle scattering from polyelectrolyte solutions dimensions of poly-(methacrylic acid) chains in salt-free solutions. Polymer 1986 27 839-842. 

There is also another interesting case, namely, when the two solvents 0 and 1 are isotopic varieties of the same chemical species (for instance, HzO and DzO). In fact, such mixtures are used to study general properties of polymer solutions by small-angle scattering. Then, one may admit that the partial volumes of the molecules belonging to the two varieties are the same. In this case, the expression of the cross-section in the zero angle limit simplifies. Equation (7.2.40) gives... 

Small-angle scattering has been the subject of numerous books and reviews and so the reader who wishes to have more precise information will find illuminating and complete discussions in books devoted either to small-angle scattering techniques or to the thermodynamics of polymers in solution [12-16]. 

Hence, as follows from eqns [28], [31], and [33], analysis of small-angle scattering from dilute polymer solution enables one to evaluate both the g5uation radius (Rg) and the second virial coefficient of the coil-coil interaction A2. 

SANS measurements were performed at room temperature (25 °C) in order to determine the sizes of the micellar self-assembled aggregates of octyl glucoside. The SANS curves of the OG micellar solutions, obtained at OG concentrations 0.038 M and 0.061 M (which are above the CMC value of OG), are shown in Eigure 1. To fit the small angles scattering intensity, /, we used the Dozier star polymer model [39] ... 

As described in Section 7.1.1, data at low (2-values probe long length-scales (D IQ), and X-ray methods have been used widely to determine chain dimensions in dilute solution, lamellar spacings in crystalline polymers, etc. [36]. As mentioned above, such measurements are referred to as small-angle scattering, though it is the g-range (typically 10 < Q < 10 which determines... 

Pedersen, J. S., Analysis of small-angle scattering data from colloids and polymer solutions modelling and least-squares fitting, Adv. Colloid Interface. ScL, 70, 171-210 (1997). 

The results on adsorbed polymers using neutron reflection provide a useful complement to studies of adsorption by small angle scattering and other classical techniques. Measurements of the excess polymer at both solution/vapour [71-73] and solution/solid [74-76] interfaces have been described. Other studies... 

The radius of gyration of polymer coils in solution can be measured using small-angle scattering. In the case of small molecules, SAXS or SANS are appropriate techniques, but if the chain is sufficiently large (coil size > X/20, where X is the wavelength of the radiation) it will scatter light anisotropically, so SALS is a suitable experiment. The radius... 

Therefore, ionomer solutions cannot be treated as a whole and cannot even be divided into only two different problems the ionomer (or associating) behavior in nonpolar solvents and the polyelectrolyte behavior in polar solvents. A new structural problem will probably arise with most of the ionomers even if some of the solution properties appear to be similar. A lot of structural studies including small angle scattering and electron microscopy experiments will be necessary to understand the structure of ionomer solutions and such studies will be very helpful to understand the structure-properties relationships of ionic polymers. 

Small angle scattering from polymers in solution. 

---