Mixed micelles light scattering, studies with

Several papers compare the properties of sulfobetaine (meth)acrylic polymers. NMR spectra and solution properties of 23a and 23b [59,60] are correlated with data from the corresponding polycarbobetaines [26]. The photophysical and solution properties of pyrene-labeled 23c were studied in terms of fluorescence emission. Addition of surfactants induces the formation of mixed micelles in aqueous solution [61]. Excluded volume effects of the unlabeled polymer were measured by light scattering [62], its adsorption on silica was studied by adsorbance measurement and ellipsometry [62,63], and the electrostimulated shift of the precipitation temperature was followed at various electric held intensities [64]. Polysulfobetaines may accelerate interionic reactions, e.g., oxidation of ferrocyanide by persulfate [65]. The thermal and dielectric properties of polysulfobetaines 23d were investigated. The flexible lateral chain of the polymers decreased Tg, for which a linear relationship with the number of C atoms was shown [66,67]. 

Schematic models for the expanded structure of bile acid-phosphatidylcholine mixed micelles are shown in Fig. 2B. The original model was proposed by Small in 1967 (S36). In this model the mixed micelle consisted of a phospholipid bilayer disk surrounded on its perimeter by bile acid molecules, which were oriented with their hydrophilic surhices in contact with aqueous solvent and their hydrophobic sur ces interacting with the hydrocarbon chains of the phosphohpid molecules. This model has recently been revised, based on further studies of mixed micelles using quasi-elastic light scattering spectroscopy (M20). In a new model for the molecular structure of bile acid-phospholipid mixed micelles. Mazer et al. (M20) propose a mixed disk, in which bile acids are found not only on the perimeter of phospholipid bilayers, but also incorporated within their interior in high concentrations (Fig. 2B). The size of these mixed micelles was estimated to be as high as 200 to 400 A in radius in some solutions, and disk-shaped particles in this size range were observed by transmission electron microscopy (M20). Micellar aggregates similar in size and structure to those found in model bile solutions have been demonstrated in dog bile (M22).

In works, " the catalytic effect of the CTAB and PM reverse micelles on the reaction of pyrimidinophanes (PPh) (Scheme 15.2) and their acyclic analogue A,A -bis(2-methylthio)-6-methylpyrimidin-4-yl)hexamethylenediamine with phosphinate 12 in chloroform is studied. The formation of the CTAB—PM mixed aggregates is proved by the NMR self-diffusion, by dielcometric titration, and by dynamic light scattering. " The micellar catalytic effect is shown to change with the size of macrocycle in the series PPh-4 < PPh-3 < PPh-2 < PPh-1. The maximum acceleration of the reaction observed at a 5 1 CTAB/PM molar ratio exceeds five orders of magnitude. 

Dubin et al. studied the formation of polyelectrolyte-micelle complexes between poly(dimethyldiallylammonium chloride) and anionic/nonionic mixed micelles by static and dynamic light scattering [21-23]. Dynamic light scattering yields the hydrodynamic radius of the particles investigated (very useful information), especially in combination with SLS, allowing an assessment of the particle architecture. 

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