| This work explores some puzzling aspects of the interaction between charged objects immersed in electrolyte solutions. From this point of view, Coulombic systems seem to display a remarkable complexity generated by the interplay between the screened electrostatic interactions, charge fluctuations and charge patterns, to name a few.; Our study of the complexation between a spherical macroion and an oppositely charged polyelectrolyte led to the discovery of the overcharging (or charge reversal) phenomenon for this system. This effect may provide an explanation for the mechanism driving the overcharging of the octameric histone in the nucleosome.; One of the long standing puzzles in colloidal science is the unexplained, confinement-induced long-range attraction between like-charge colloids. We showed, contrary to previous belief, that two colloidal particles confined by a finite cylindrical shell of arbitrary cross section do not always repel (as is the case when the cylinder is infinite). The finite longitudinal confinement can be conceivably realized by other colloids since all measurements are done at finite concentration.; The important role charge patterns can play in the interactions between molecules is exemplified in our experimental evidence and theoretical explanation of the sequence dependent DNA condensation.; We also present some preliminary results of field theory calculations on the controversial subject of criticality in ionic fluids. |
