Efficient antibacterial surfactants have been prepared by the quaternization of the amino groups of poly(ethylene-co-butylene)-b-poly[2-(dimethylamino)ethylmethacrylate] (PEB-b-PDALkEMA) diblock copolymers by octyl bromide. The diblock copolymers have been synthesized by ATRP of 2-(dimethylamino)ethylmethacrylate (DMAEMA) initiated by an activated bromide-end-capped poly(ethylene-co-butylene). In the presence of CuBr, 1,4,7,10,10-hexamethyl-triethylenetetramine (HMTETA), and toluene at 50 degrees C, the initiation is slow in comparison with propagation. This situation has been improved by the substitution of CuCl for CuBr, all the other conditions being the same. Finally, the addition of an excess Of CuCl2 (deactivator) to the CuCl/HMTETA catalyst is very beneficial in making the agreement between the theoretical and experimental number-average molecular weights excellent. The antibacterial activity of PEB-b-PDMAEAM quaternized by octyl bromide has been assessed against bacteria and is comparable to the activity of a commonly used disinfectant, that is, benzalkonium chloride. (c) 2005 Wiley Periodicals, Inc.