Ten surfactants prepd., viz., cyclohexyloxymethyidimethyloctyl(decyl, dodecyl, tetradecyl or hexadecyl)ammonium chlorides and 3-cyclohexyloxymethyl-1-octyl(decyl, dodecyl tetradecyl or hexadecyl)imidazolium chlorides, reduced surface tension to 45.4-31.9 mN/m, had mol. surface areas varying over (83-92)center dot 10(-20)m(2), surface excess 1.99-1.81 mu mol/m(2), crit. micelle concns. 4.17-0.50 mmol/l., surface tension at cmc 45.4-31.9 mN/m, adsorption free energies Delta G degrees 27.7-39.7 kJ/moL The imidazole ring increased the mols. by 5% in surface area, made them reduce surface tension to values by 3-6 mN/m lower, and attain cmc at concns. lower than the resp. values shown by the dimethylalkylammonium analogs. Not only elongation of the hydrophobic substituent but also modification of the N atom and its environment allowed the surface properties to be controlled. Szszkowski's equation coeffs. were evaluated