Dynamical properties in dense triblock copolymer micellar system

We present results of analyses of an extensive set of dynamic light scatter ing (PCS) and viscoelastic (frequency dependent complex moduli) measurement s in concentrated aqueous solutions of a triblock copolymer L64 (PEO13PPO30 PEO13) micellar system at different temperatures. In particular we study th e system dynamical properties in a region of the phase diagram characterize d by the existence of a percolation process and a kinetic glass transition. Both the processes, temperature and concentration dependent, are related w ith adhesive interaction between micelles. The intermediate scattering func tion (ISF) shows an ergodic to non-ergodic transition on crossing a tempera ture and concentration dependent line. Viscoelasticity data, determined by means of frequency-dependent complex moduli, satisfy the scaling relations predicted by the scalar elasticity percolation theory and well account for the glass transition process, give indication that percolation and the ergo dic non-ergodic transitions take places in separate regions of the phase di agram. Detailed analysis of ISF and theological data, conducted in terms of the mode coupling theory (MCT) gives evidence of a logarithmic decay on th e density fluctuations, which could be attributed to a higher order singula rity, followed by a power-law behavior. (C) 2001 Published by Elsevier Scie nce B.V. All rights reserved.