Abstract
H-1 NMR relaxation is used to study the self-assembly of a double thermoresponsive diblock copolymer in dilute aqueous solution. Above the first transition temperature, at which aggregation into micellar structures is observed, the trimethylsilyl (TMS)-labeled end group attached to the shell-forming block shows a biphasic T-2 relaxation. The slow contribution reflects the TMS groups located at the periphery of the hydrophilic shell, in agreement with a star-like micelle. The fast T-2 contribution corresponds to the TMS groups, which fold back toward the hydrophobic core, reflecting a flower-like micelle. These results confirm the formation of block copolymer micelles of an intermediate nature (i.e., of partial flower-like and star-like character), in which a part of the TMS end groups folds back to the core due to hydrophobic interactions. image
| Original language | English |
|---|---|
| Pages (from-to) | 915-919 |
| Number of pages | 5 |
| Journal | Macromolecular Chemistry and Physics |
| Volume | 215 |
| Issue number | 9 |
| DOIs | |
| Publication status | Published - May 2014 |
Funding
Financial support for Access to Research Infrastructures (EC-FP7 project number: 261863, Bio-NMR) and funding by the German Research Council (Deutsche Forschungsgemeinschaft DFG), grant LA611/4 are gratefully acknowledged. The authors thank Dr. A. de Graaf and Prof. W. E. Hennink (Utrecht University) for fruitful discussions.
Keywords
- block copolymers
- polymer micelles
- relaxation NMR spectroscopy
- self-assembly
- thermoresponsive materials
- POLY(ETHYLENE OXIDE)
- LIGHT-SCATTERING
- MICELLIZATION
- WATER
- TEMPERATURE
- DELIVERY