EFFECT OF UREA ON BIOMIMETIC AGGREGATES

The effect of urea on biomimetic aggregates (aqueous and reversed mice lles, vesicles and monolayers) was investigated to obtain insights int o the effect of the denaturant on structured macromolecules. Direct ev idence obtained from light scattering (static and dynamic), monolayer maximum isothermal compression and ionic conductivity measurements, to gether with indirect evidence from fluorescence photodissociation, flu orescence suppression, and thermal reactions, strongly indicates the d irect interaction mechanism of urea with the aggregates. Preferential solvation of the surfactant headgroups by urea results in an increase in the monomer dissociation degree (when applied), which leads to an i ncrease in the area per headgroup and also in the loss of counterion a ffinities.