Low hydrophobically modified (with dodecylamide chain) linear poly(acrylic acid) sodium salts (LHMPAANa) of various degrees of grafting (tau) and molecular weights were synthesized and used as emulsifiers of the n-dodecane/water (NaNO3 10(-3) M) system. Stability and how properties of the resulting n-dodecane in water emulsions (dispersed phase volume fraction = 0.5) were investigated as a function of tau (tau = 0 to 10% in mel), molecular weight (5000, 50,000, and 150,000 g/mol) and polymer concentration (0 to 10%). It was clearly shown that viscosification (via an associating mechanism of LHMPAANa) of the external phase of emulsions is a key factor in explaining dispersion breakdown. However, a complete description of the phenomenon could not be achieved without considering the adsorption of the polymer at the liquid-liquid interface which depends closely on tau but not much on molecular weight. The molecular weight effects were found to be restricted to the viscosification of the outer phase.