The formation and the properties of wormlike micelles in aqueous solutions of mixed cationic and anionic gemini surfactants, 2-hydroxyl-propanediyl-alpha-omega-bis(dimethyldodecylammonium bromide) (12-3(OH)-12) and O,O'-bis(sodium 2-dodecylcarboxylate)-p-benzenediol (C-12 phi C-12), have been studied by steady-state and dynamic rheological measurements at 25 degrees C. With the addition of a small amount of C-12 phi C-12 into the solution of 12-3(OH)-12, the total surfactant concentration of which was always kept at 80 mmol L-1, the solution viscosity was strongly enhanced and its maximum was much larger than that of the mixed system of propanediyl-alpha-omega-bis(dimethyldodecylammonium bromide) (12-3-12) and C-12 phi C-12. The results of dynamic rheology measurements showed that 12-3(OH)-12/C-12 phi C-12 formed longer wormlike micelles in comparison with 12-3-12/C-12 phi C-12. This was attributed to the effect of hydrogen bonding occurring between 12-3(OH)-12 molecules, which was an effective driving force promoting micellar growth. As few C-12 phi C-12 participated in the micelles, the electrostatic attraction between the oppositely charged head groups of 12-3(OH)-12 and C-12 phi C-12 made the molecules in the aggregates pack more tightly. This reinforced the hydrogen-bonding interactions and greatly promoted the micellar growth. (C) 2010 Elsevier Inc. All rights reserved.