Aggregation behavior of amphiphilic poly(2-alkyl-2-oxazoline) diblock copolymers in aqueous solution studied by fluorescence correlation spectroscopy

• Published in: Colloid and polymer science 2004-06, Vol.282 (8), p.833-843
• Main Authors: BONNE, Tune B, LÜDTKE, Karin, JORDAN, Rainer, STEPANEK, Petr, PAPADAKIS, Christine M
• Format: Article
• Language: English
• Subjects: Agglomeration; Annealing; Applied sciences; Aqueous solutions; Copolymers; Correlation analysis; Exact sciences and technology; Fluorescence; Micelles; Organic polymers; Physicochemistry of polymers; Properties and characterization; Solution and gel properties; Spectroscopy; Spectrum analysis
• ISSN: 0303-402X; 1435-1536
• DOI: 10.1007/s00396-004-1131-2

The diffusional behavior of amphiphilic poly(2-oxazoline) diblock copolymers in aqueous solution is studied using photon correlation spectroscopy (PCS) and fluorescence correlation spectroscopy (FCS). The polymers were synthesized by living cationic polymerization and were fluorescence-labeled with tetramethyl rhodamine isothiocyanate either at the end of the hydrophilic or the hydrophobic block. Temperature-resolved PCS showed that, at room temperature, large metastable aggregates are present along with unimers and micelles. An annealing above ~40 °C resulted in stable equilibrium micellar solutions. By means of FCS, the hydrodynamic radii of the unimers and the micelles were measured simultaneously in a broad concentration range, and the critical micelle concentration could be determined. Comparison of the results from conventional PCS measurements with this first FCS study showed excellent agreement and the high potential of the FCS technique.[PUBLICATION ABSTRACT] Erratum DOI: 10.1007/s00396-004-1196-y