Aggregation of Pluronic F127 and Polydimethylsiloxane-graft-polyether Block Copolymers in Water and Microstructure of Aggregates as Evaluated by Molecular Probe Techniques

A comparative investigation of the aggregation in aqueous solution of a poly(ethylene oxide)-poly(propylene oxide)poly(ethylene oxide) block copolymer (PEO-PPO-PPO) (Pluronic F127) with a polydimethylsiloxane-graft-polyether (PDMS-PEO) has been done. The spectroscopic parameters obtained from absorption spectra of the 4,4,5,5tetramethylimidazoline-1-oxyl-3-oxide-2-undecyl (TEMIDO-undecyl) and fluorescence spectra of pyrene and 1,10-bis(1-pyrene)decane (PD) in aqueous solutions of block copolymers allowed the evaluation of the critical micellization concentration (CMC), its variation with temperature, as well as micropolarity and microviscosity sensed by the probe in its environment. The effect of different concentrations of n-hexanol, added in PDMS-PEO micelles, is evidenced by the variation of monomer and excimer parameters of the PD probe.