INTERACTION OF FLUORESCENT DYE LABELED (HYDROXYPROPYL)CELLULOSE WITH NONIONIC SURFACTANTS

Recently, Brackman et al. reported the formation of complexes between a neutral water-soluble polymer, polypropylene oxide) (PPO, MW 1000) and a neutral surfactant, n-octyl β-D-thioglucopyranoside (OTG).1 An important feature of this work is that it is the first account of the unambiguous detection of complexes between neutral polymers and neutral surfactants. Until now it was generally believed that neutral surfactants are indifferent toward neutral polymers.1,2 Brackman et al. detected polymer/micelle complexes by microcalorimetry and turbidity measurements. They also reported that the surfactant has the same critical micelle concentration (cmc) in the presence of PPO as it does in water. This is in contrast to the situation encountered with all ionic surfactants, for which association with neutral polymers is always accompanied by a decrease in cmc.3 It is only for the PPO-OTG system that Brackman et al. reported unequivocal evidence for polymer/micelle complex-ation, although they carried out measurements also with poly (ethylene oxide), poly (N-vinylpyrrolidone), poly (vinyl alcohol)-poly(vinyl acetate) copolymer, and (hydroxypropyl)cellulose (HPC). They found that the cmc of the surfactant did not change in the presence of those polymers. Nevertheless, it is not excluded that complexes were formed but remained undetected by the measurements. This note reports evidence for the formation of complexes between HPC and two neutral surfactants: OTG and n-octyl β-D-glucopyranoside (OG). The evidence stems from experiments with a pyrene-labeled (hydroxypropyl)cellulose (HPC/Py). © 1990, American Chemical Society. All rights reserved.