High-Pressure Micellar Solutions of Symmetric and Asymmetric Styrene?Diene Diblocks in Compressible Near Critical Solvents: Micellization Pressures and Cloud Pressures Respond but Micellar Cloud Pressures Insensitive to Copolymer Molecular Weight, Concentration, and Block Ratio Changes

Journal Article · Thu Jan 01 04:00:00 EST 2009 · Macromolecules

DOI:https://doi.org/10.1021/ma900270u· OSTI ID:962621

Winoto, Winoto ^[1]; Tan, Sugata ^[1]; Shen, Youqin ^[1]; Radosz, Maciej ^[1]; Hong, Kunlun ^[2]; Mays, Jimmy ^[2]

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1. University of Wyoming, Laramie
2. ORNL

Micellar solutions of polystyrene-block-polybutadiene and polystyrene-block-polyisoprene in propane are found to exhibit significantly lower cloud pressures than the corresponding hypothetical nonmicellar solutions. Such a cloud-pressure reduction indicates the extent to which micelle formation enhances the apparent diblock solubility in near-critical and hence compressible propane. Concentration-dependent pressure-temperature points beyond which no micelles can be formed, referred to as the micellization end points, are found to depend on the block type, size, and ratio. The cloud-pressure reduction and the micellization end point measured for styrene-diene diblocks in propane should be characteristic of all amphiphilic diblock copolymer solutions that form micelles in compressible solvents.

• Research Organization: Oak Ridge National Laboratory (ORNL); Center for Nanophase Materials Sciences
• Sponsoring Organization: SC USDOE - Office of Science (SC)
• DOE Contract Number: AC05-00OR22725
• OSTI ID: 962621
• Journal Information: Macromolecules, Journal Name: Macromolecules Journal Issue: 11 Vol. 42
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
BUTADIENE
COPOLYMERS
MICELLAR SYSTEMS
ORGANIC POLYMERS
POLYSTYRENE
PROPANE
SOLUBILITY
SOLVENT PROPERTIES