https://nathan.instras.com/documentDB/paper-311.pdf

Poly(ethylene oxide)-poly(propylene oxide )-poly (ethylene oxide) block copolymer surfactants in aqueous solutions and at interfaces: thermodynamics, structure, dynamics, and modeling

— Pyrene fluorescence spectra have been run in 62 solvents of widely differing solvent polarity. As has been noted previously, the intensity ratio of the first (the 0–0 band) and third bands in vibronic fine structure of these spectra are very sensitive to solvent polarity. These I1/I3 values, however, are not sensitive to hydrogen bonding aspects of solvent-solute interactions. Correlations are reported with Winstein's Y values and with Dimrotb's ET values. On this basis the I1/I3 values for pyrene fluorescence are suggested as the basis for a new empirical scale of solvent polarity, called the Py scale, which offers certain conveniences over other scales of solvent polarity.

THE Py SCALE OF SOLVENT POLARITIES. SOLVENT EFFECTS ON THE VIBRONIC FINE STRUCTURE OF PYRENE FLUORESCENCE and EMPIRICAL CORRELATIONS WITH ET and Y VALUES

Fluorescence methods in the study of the interactions of surfactants with polymers

Investigation of human erythrocyte ghost membranes with intramolecular excimer probes

Fate of excited probes in micellar systems.

— The molecule (1,1'-dipyrenyl)-methyl ether [dipyme] shows intramolecular excimer fluorescence in competition with fluorescence from the locally excited pyrene chromophore. This intensity ratio Ic/Im is sensitive to solvent viscosity. The molecule is soluble in synthetic phospholipid membranes. 1H NMR studies suggest that the molecule is localized in the hydrocarbon region of the membrane. Fluorescence measurements at various temperatures of dipyme dissolved in these membranes show that Ic/Im is exceedingly sensitive to fluidity changes accompanying both the pretransitions and the gel to liquid crystalline transitions of the membrane. These studies can be carried out at a mole ratio of probe to lipid 102-103 smaller than that necessary to observe bimolecular pyrene excimer formation.

D. Georgescauld

Papers

Intramolecular excimer fluorescence: a new probe of phase transitions in synthetic phospholipid membranes