ABSTRACT
The dynamics of near-surface conformations in complex fluids under flow should dramatically affect their rheological properties. We have made the first measurements resolving the decay kinetics of a hexagonal phase induced in a threadlike polyionic micellar system under Poiseuille shear near a quartz surface. Upon cessation of shearing flow, this minimum interference crystalline phase formed within approximately 20 microm of the surface "melts" to a metastable two-dimensional liquid of aligned micelles in approximately 0.7 s. This is some three orders of magnitude shorter than the time required for bulk (Couette) shear-aligned micelles in this system to reach a fully entangled state.
ABSTRACT
The combination of fast atom bombardment with charge-remote fragmentation using a hybrid (BEqQ) mass spectrometer was used successfully to assess and localize the extent of selective deuterium isotope labeling of tetradecyItrimethylammonium bromides. Spectral details reveal a new reaction that can give rise to ions isobaric with those formed by chargeremote fragmentation.
ABSTRACT
The present state of the field of biopolymers solubilized in apolar solvents via reverse micelles is reviewed. First, an extensive discussion of the physical and chemical properties of reverse micelles is presented. Particular attention is devoted to the nature of water in the water pools of reverse micelles; to the structure and shape of the micellar aggregates; and to the dynamic properties of the reverse micelles. In the second part of the paper, the mechanism of solubilization of proteins and nucleic acids in hydrocarbon reverse micelles is discussed. Spectroscopic data, mostly circular dichroism and fluorescence, are reviewed in order to clarify the conformational changes which the biopolymers undergo upon their uptake into the micellar environment and determine the location of the biopolymers inside the reverse micelles. Data from neutron scattering, light scattering, ultracentrifugation, and electron microscopy of the protein-containing micelles are reviewed and discussed with the aim of illustrating the structure of the micellar aggregates containing the biopolymer as guest molecules. The activity of enzymes and nucleic acids is discussed, with emphasis on the influence upon the chemical reactivity brought about by the micellar parameters. Finally, a brief review of the applications and potentialities of biopolymer-containing reverse micelles is presented.
