Interfacial Micellar Structures from Novel Amphiphilic Star Polymers
| Autor: | Kirsten L. Genson, Joshua Hoffman, Jing Teng, Vladimir V. Tsukruk, David Vaknin, Eugene R. Zubarev |
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| Rok vydání: | 2004 |
| Předmět: |
Models
Molecular Materials science Surface Properties Acrylic Resins Micelle chemistry.chemical_compound X-Ray Diffraction Monolayer Amphiphile Polymer chemistry Electrochemistry Molecule General Materials Science Particle Size Micelles Spectroscopy Acrylic acid chemistry.chemical_classification Molecular Structure Air Water Surfaces and Interfaces Polymer Condensed Matter Physics Core (optical fiber) chemistry Chemical engineering Polystyrenes Polystyrene |
| Zdroj: | Langmuir. 20:9044-9052 |
| ISSN: | 1520-5827 0743-7463 |
| DOI: | 10.1021/la048548x |
| Popis: | An amphiphilic heteroarm star polymer containing 12 alternating hydrophobic/hydrophilic arms of polystyrene (PS) and poly(acrylic acid) (PAA) connected to a well-defined rigid aromatic core was studied at the air-water and the air-solid interfaces. At the air-water interface, the molecules spontaneously form pancakelike micellar aggregates which measure up to several microns in diameter and 5 nm in thickness. Upon reduction of the surface area per molecule to 7 nm2, the two-dimensional micelles merged into a dense monolayer. We suggest that confined phase separation of dissimilar polymer arms occurred upon their segregation on the opposite sides of the rigid disklike aromatic core, forcing the rigid cores to adopt a face-on orientation with respect to the interface. Upon transfer onto solid supports the PS chains face the air-film interface making it completely hydrophobic, and the PAA chains were found to collapse and form a thin flattened underlayer. This study points toward new strategies to create large 2D microstructures with facial amphiphilicity and suggests a profound influence of star molecular architecture on the self-assembly of amphiphiles at the air-water interface. |
| Databáze: | OpenAIRE |
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