Masayuki Aikawa

Photoluminescence methods for evaluation of solubilization parameters and dynamics or micellar aggregates. Limiting cases which allow estimation of partition coefficients, aggregation numbers, entrance and exit rates

Abstract Poisson statistics is a nature consequence of a distribution of solubilized molecules among micellar aggregates. With postulates of non-cooperativity and thermodynamic considerations, relationships for extent of solute fractionation between the micellar phase and the aqueous phase are derived, as are expressions for the handling of experimental data from the quenching of photoluminescence probes of micellar aggregates.

DYNAMICS OF MOLECULAR OXYGEN IN MICELLAR SOLUTIONS

Abstract Fluorescence quenching by molecular oxygen has been employed to estimate dynamic parameters and solubility characteristics of molecular oxygen in micelle forming detergent solutions. A kinetic model which assumes that oxygen quenching occurs only in the micellar phase is employed to analyze the data.

Photoluminescence probes of micelle systems. Cyclic azoalkanes as quenchers of 1,5-dimethylnaphthalene fluorescence

Abstract Quenching of the fluorescence of detergent solutions of 1,5-dimethylnaphthalene by a series of bicyclic azoalkanes has been investigated. A model is employed which postulates that the azo quenchers are partitioned between the aqueous phase and micelles.

Electron transport reactions between pyrene and methylviologen in a model biological membrane

Electron transport reactions in a phospholipid vesicle solution have been investigated by time-resolved laser spectroscopy. Photoelectrons were produce by two-photon absorption of the pyrene chromophore adsorbed in a model membrane (vesicle) and were captured either by bound pyrene, which was covalently attached to the surfactant molecule anchored in the hydrophobic bilayer of the membrane, or by methylviologen which was located in the outer water phase of the vesicle solution. The lifetimes and yields of pyrene fluorescence and of the lowest pyrene triplet state were not affected by the addition of methylviologen.

USEFUL PHOTOLUMINESCENCE PROBES OF MICELLAR SYSTEMS—CYCLIC AZOALKANES AS FLUORESCENCE ACCEPTORS AND 1,5-DIMETHYLNAPHTHALENE AS A FLUORESCENCE DONOR

Abstract— Certain cyclic azoalkanes are shown to exhibit substantial fluorescence intensity and attractive absorption parameters in detergent solutions. Quenching of the fluorescence of detergent solutions of 1,5‐dimethylnaphthalene by these bicyclic azoalkanes has been investigated and is found to provide a useful system to study properties of micellar systems.

Application of laser photolysis to the study of reactive intermediates

Excimer laser flash photolysis in the study of diphenyl carbene (DPC) reveals the presence of at least three transient species produced by excitation of a precursor at 249 nm in isooctane solution at room temperature depending on the concentration of O2present. In an aerated solution, a fast first-order decay assigned to3DPC leads to the formation of an unassigned species which also decays by first order kinetics to produce the observed product Ph2CO. In degassed solution, the fast first-order decay of a species to produce3DPC which decays by second-order kinetics to produce the dimeric products observed.