A periodic structure in a mixture of D2O/3-methylpyridine/NaBPh4 induced by solvation effect

The effect of adding sodium tetraphenylborate (NaBPh4) on a LCST type phase separation of a mixture of D2O and 3-methylpyridine is investigated by visual observation and small-angle neutron scattering (SANS). In the case that the amount of salt is smaller than 50 mM, the mixture colors below the phase separation temperature. When the amount of salt is increased, the phase separation disappears and a single peak profile is observed at finite-Q by SANS. These results indicate that a periodic structure is induced in one phase region by the addition of NaBPh4.