Block copolymers static light scattering

Structural characterization of block copolymer aggregates by dynamic and static light scattering (DLS and SLS) in combination with small angle neutron scattering (SANS) at variable ionic strength and pH in the solution enables one to discriminate between frozen and dynamic (equilibrium) micelles. In particular, SANS provides direct information about the core size and shape because of relatively low scattering density of the corona. 

The same type of diblock copolymer with slightly different block length was also characterized by Castro et al. with respect to its interaction with SDS [112]. The polymer is poly(styrene oxide)-PEO with 17 and 65 monomer units, respectively. In aqueous solution, this polymer forms micelles with a hydrodynamic radius of approximately 12.7 nm and an aggregation number of ca. 150 [113]. On the basis of measurements of the dissymmetry of the static light scattering intensity [114], the structure of the formed polymer micelles was found to be spherical [113]. The erne of this type of diblock copolymer was found to be very low. 

Khougaz, K., Gao, Z., and Ei senberg, A. (1994) Determination of the critical micelle concentration of block copolymer micelles by static light scattering. Macromolecules, 27,6341-6346. 

Lodge [102] and Norman [103] reviewed the use of scattering techniques in the characterization of polymers, particularly block copolymers. Static and dynamic light scattering, small-angle neutron and X-ray reflectivity were analyzed and emphasis was placed on their similarities and differences. 

Brown, W Schillen, K Hvidt, S, Triblock Copolymers in Aqueous Solution Studied by Static and Dynamic Light Scattering and Oscillatory Shear Measurements. Influence of Relative Block Sizes, Journal of Physical Chemistry 96, 038, 1992. 

High-pressure static and dynamic light scattering were used to closely examine the behavior of block copolymers of poly(vinyl acetate) (PVAc) and poly(l,l,2,2-tetrahydroperfluoroalkyl acrylate (PTAN) as a function of C02 density (Buhler et al., 1998). The phase diagram for PVAc-6-TAN shows three distinct phases as a function of polymer concentration and C02 density at a fixed temperature of 45 °C (see Figure 9.1). The block copolymer forms a precipitated phase at low C02 densities, spherical micelles at intermediate C02 densities, and unimers, or free polymer chains in solution, at high densities. The micelles-to-unimer transition was found to be very... 

The internal structure of polyelectrolyte block copolymer micelles such as their core radius Rc and micellar radius Rm can be determined by a variety of methods involving static and dynamic light scattering (SLS, DLS), small-angle X-ray (SAXS) and neutron scattering (SANS) as well as imaging techniques such as transmission electron microscopy (TEM) or atomic force mi-... 

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