TY - JOUR
T1 - Role of the tracer in characterizing the aggregation behavior of aqueous block copolymer solutions using fluorescence correlation spectroscopy
AU - Bonné, Tune B.
AU - Papadakis, Christine M.
AU - Lüdtke, Karin
AU - Jordan, Rainer
PY - 2007/2
Y1 - 2007/2
N2 - The hydrodynamic radii of micelles formed by amphiphilic poly(2-alkyl-2-oxazoline) diblock copolymers in aqueous solution determined using fluorescence correlation spectroscopy (FCS) depend on the nature of the fluorescent tracer used. We have compared the values of the hydrodynamic radii of the unimers and the micelles as well as the critical micelle concentrations (CMC), using as tracers (1) the identical diblock copolymers being fluorescence-labeled at the hydrophilic or the hydrophobic block terminus [Bonné et al. Colloid Polym Sci (2004) 282:833-843], and (2) a low molar mass fluorescence dye, rhodamine 6G. Whereas similar values for the CMC were found for both probes, the hydrodynamic radius of micelles is significantly underestimated using a free dye as a tracer in FCS, especially near the CMC. We attribute this discrepancy to the fast exchange of the dye between micelles and solution.
AB - The hydrodynamic radii of micelles formed by amphiphilic poly(2-alkyl-2-oxazoline) diblock copolymers in aqueous solution determined using fluorescence correlation spectroscopy (FCS) depend on the nature of the fluorescent tracer used. We have compared the values of the hydrodynamic radii of the unimers and the micelles as well as the critical micelle concentrations (CMC), using as tracers (1) the identical diblock copolymers being fluorescence-labeled at the hydrophilic or the hydrophobic block terminus [Bonné et al. Colloid Polym Sci (2004) 282:833-843], and (2) a low molar mass fluorescence dye, rhodamine 6G. Whereas similar values for the CMC were found for both probes, the hydrodynamic radius of micelles is significantly underestimated using a free dye as a tracer in FCS, especially near the CMC. We attribute this discrepancy to the fast exchange of the dye between micelles and solution.
KW - Aggregation behavior
KW - Amphiphilic block copolymers
KW - Fluorescence correlation spectroscopy
KW - Polymer physics
UR - http://www.scopus.com/inward/record.url?scp=33846702052&partnerID=8YFLogxK
U2 - 10.1007/s00396-006-1616-2
DO - 10.1007/s00396-006-1616-2
M3 - Article
AN - SCOPUS:33846702052
SN - 0303-402X
VL - 285
SP - 491
EP - 497
JO - Colloid and Polymer Science
JF - Colloid and Polymer Science
IS - 5
ER -