TY  - JOUR
A1  - Inal, Sahika
A1  - Chiappisi, Leonardo
A1  - Kölsch, Jonas D.
A1  - Kraft, Mario
A1  - Appavou, Marie-Sousai
A1  - Scherf, Ullrich
A1  - Wagner, Manfred
A1  - Hansen, Michael Ryan
A1  - Gradzielski, Michael
A1  - Laschewsky, André
A1  - Neher, Dieter
T1  - Temperature-regulated fluorescence and association of an Oligo(ethyleneglycol)methacrylate-based copolymer with a conjugated Polyelectrolyte-the effect of solution ionic strength
JF  - The journal of physical chemistry : B, Condensed matter, materials, surfaces, interfaces & biophysical chemistry
N2  - Aqueous mixtures of a dye-labeled non-ionic thermoresponsive copolymer and a conjugated cationic polyelectrolyte are shown to exhibit characteristic changes in fluorescence properties in response to temperature and to the presence of salts, enabling a double-stimuli responsiveness. In such mixtures at room temperature, i.e., well below the lower critical solution temperature (LCST), the emission of the dye is strongly quenched due to energy transfer to the polycation, pointing to supramolecular interactions between the two macromolecules. Increasing the concentration of salts weakens the interpolymer interactions, the extent of which is simultaneously monitored from the change in the relative emission intensity of the components. When the mixture is heated above its LCST, the transfer efficiency is significantly reduced, signaling a structural reorganization process, however, surprisingly only if the mixture contains salt ions. To elucidate the reasons behind such thermo- and ion-sensitive fluorescence characteristics, we investigate the effect of salts of alkali chlorides, in particular of NaCl, on the association behavior of these macromolecules before and after the polymer phase transition by a combination of UV-vis, fluorescence, and H-1 NMR spectroscopy with light scattering and small-angle neutron scattering measurements.
Y1  - 2013
U6  - https://doi.org/10.1021/jp408864s
SN  - 1520-6106
VL  - 117
IS  - 46
SP  - 14576
EP  - 14587
PB  - American Chemical Society
CY  - Washington
ER  -