Molecular environment and reactivity in gels and colloidal solutions under identical conditions.

A PEG-Tyr block copolymer forms a kinetically stable colloidal solution in water at room temperature which undergoes an irreversible conversion to a gel phase upon heating. A micellar solution and a gel can therefore be studied under identical experimental conditions. This made it possible to compare physical properties and chemical reactivity of micelles and gels in identical chemical environments and under identical conditions.

Effect of humidity on photoinduced radicals in human hair.

EPR spectroscopy was used to monitor formation of free radicals in human hair upon UV irradiation. While the EPR spectra of brown hair were dominated by melanin signal, those of white hair were keratin-derived. The decay of UV induced keratin radicals was enhanced at increased ambient humidity.