Micelles formed from photochemically active amphiphiles: Structural characterization by small-angle neutron scattering

A novel class of photochemically active amphiphiles has been synthesized containing a ketone moiety as a biradical or radical pair precursor on the hydrophobic tail of sodium sulfate surfactants. Alteration of the molecular structure of each ketone-containing surfactant allows for the systematic and predictable manipulation of the micellar size and shape, both of which are important in determining the coupling between the unpaired electrons confined within the micelle and the intraradical dynamics. The structure of the resulting aggregates has been analyzed by small-angle neutron scattering (SANS). The results show that the amphiphiles form ellipsoidal micelles with aggregation numbers between 30 and 150 that depend on the balance between monomer dimensions and steric effects caused by the atomic spatial arrangement within the hydrophobic tail of the different surfactants.