Water-induced micelle formation of block copoly(oxyethylene-oxypropylene-oxyethylene) in o-xylene

Journal Article · Mon Apr 12 00:00:00 EDT 1993 · Macromolecules; (United States)

DOI:https://doi.org/10.1021/ma00060a047· OSTI ID:6784102

Wu, Guangwei; Zhou, Zukang; Chu, B ^[1]

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1. State Univ. of New York, Stony Brook (United States)

Static and dynamic light scattering, viscometry, NMR, and vapor pressure osmometry techniques have been employed to study the water-induced micellization behavior of poly(oxyethylene-oxypropylene-oxyethylene) block copolymer, Pluronic L64, in o-xylene solution. Results show that Pluronic L64 does not form polymolecular micelles in the absence of water or in the presence of a small amount of water (molar ratio water/EO < 0.15). Micelles, consisting of a PPO shell and a PEO and H[sub 2]O core, are formed when the water to EO molar ratio (Z) in the micelle is greater than 0.2. For Z < 1.3, spherical micelles with an average hydrodynamic radius R[sub h] of ca. 9.2 nm are formed, with R[sub h] almost independent of Z. For Z > 1.3, both the aggregation number and the hydrodynamic radius become dependent on the Z value, then the micelle shape could be nonspherical. As experimentally evidenced by NMR spectra, the solubilized water can be classified into bound water and free water. Most likely, water is not evenly distributed in the core, as the environments of EO units at different positions in the block copolymer are not identical.

• DOE Contract Number: FG02-86ER45237
• OSTI ID: 6784102
• Journal Information: Macromolecules; (United States), Journal Name: Macromolecules; (United States) Vol. 26:8; ISSN MAMOBX; ISSN 0024-9297
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201* -- Chemical &amp; Physicochemical Properties
ALKYLATED AROMATICS
AROMATICS
CHEMICAL PROPERTIES
COPOLYMERS
FLUID MECHANICS
HYDROCARBONS
HYDRODYNAMICS
HYDROGEN COMPOUNDS
LIGHT SCATTERING
MECHANICS
NMR SPECTRA
ORGANIC COMPOUNDS
ORGANIC POLYMERS
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
POLYMERS
SCATTERING
SPECTRA
THERMODYNAMIC PROPERTIES
VAPOR PRESSURE
WATER
XYLENES