How Do Ion Specific Effects Operate in Ethylammonium Nitrate?

In recent work we have found that tetradecylpyridinium bromide (TPBr) and tetradecylpyridinium chloride (TPC) dissolved in the protic ionic liquid (IL) ethylammonium nitrate (EAN) have different critical micelle concentrations (0.130 M versus 0.163 M, respectively) and form different shaped micelles (oblate ellipsoids versus spherical, respectively). As the nitrate concentration is ~ 100x higher, it is remarkable that the surfactant counterion (Cl- or Br-) has any effect on the cmc or micelle shape. This reveals ion specific effects operate ion ILs, even when the added ion concentration is orders of magnitude less than the concentration IL ions. This experiment will examine EAN mixed with the surfactant headgroups tetrametylammonium (TMA+) or methylpyridinium (MP+) in the presence of ethylammonium chloride (EACl) or ethylammonium broimide (EABr).