engleski

Interaction of Triton X-100 Micellar Aggregates with alpha-PbF2 at Steady-State Condition. Size and Particle Size Distribution Using SLS and DLS Method

The kinetic study of alpha-PbF2 crystal growth at 25 oC from the equimolar solution (a(Pb2+)/a(F-)=1/2) of relatively low supersaturation with constant a(F-) and pHeq =5.3, utilizing "neutral" crystal growth promoter and inhibitor:non-ionic surfactant Triton X-100 was described (1). In this work the results of adsorption/desorption, shown two steps Langmuir isotherms, will be presented, taking place in surfactant concentration range from cmc, below and above c1 (c1 is about 10xcmc, critical micellization concentration) The fluctuation in adsorption/desorption amount coincides with the fluctuation in pF-stat rate of crystallization normalized to the mass increment of PbF2 grown, and also in the same way with the fluctuation in calculated relative supersaturation as a function of T-X-100 concentration: it is caused exclusively by its interactions with the lattice ions. In the mentioned concentration range the primary spherical micelles, followed by their growth to gaint spherical aggregates, and finally into elongated double warm like chains, were transformed. These transformations were directly visualized by polarizing microscope with lambda plate examinations in micron scale range. The characterization of these different micellar aggregates in submicron range will be presented, as determined by SLS and DLS method (evaluation of size and particle size distribution at dynamic condition of steady-state). (1) N.Stubičar, K.Banić, and M.Stubičar:Kinetics of crystal growth of alpha-PbF2 and micellization of non-ionic surfactant Triton X-100 at steady-state condition, submitted to Progress in Colloid Polymer Sci.(Opaska: published: 100(1996)221-229. Abstract classification:11H.

alpha lead fluoride. distributions of hydrodynamic diameters; dynamic light scattering method; kinetics and mechanism of promotion and inhibition of growth; micelles of Triton X-100; pF-stat method; polarizing microscopy.

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