Viscometry under Newtonian flow conditions has been used to study morphological changes in 0.3 M sodium dodecyl sulfate (SDS) micellar solutions in the presence of aliphatic amines (n-heptyl, C7NH2, or n-octyl, C8NH2) and different inorganic (MCl, M = Li, Na, K, or Rb; and NaX, X = Cl, Br, or SCN), organic salts (NaY, Y = salicylate (Sal), benzoate (Ben), anthranilate (An), or tosylate (Tos)), symmetrical quaternary bromides (R4NBr, R = H, CH3, C2H5, n-C3H7, n-C4H9, or n-C5H11) or tetrabutylphosphonium bromide, (n-C4H9)(4)PBr, at 30 degrees C. Addition of amines with or without organic/inorganic salts causes the usual viscosity increase until the phase boundary of the L-1 phase is reached. However, in the presence of quaternary bromides, viscosity-[amine] profiles show an increase, a plateau, and slower decrease regions. The appearance of these regions has been found to be dependent on the chain length of the R-part and [quaternary bromide]. These effects have been discussed on the basis of solubilization of aliphatic amines in a micellar palisade layer or micellar exterior and their possible effects on the packing parameter and micellar morphology.