A new kind of amphiphilic random copolymers has been synthesized by radicalcopolymerization of quaternary alkyl salts of dimethylaminoethyl methacrylate(QASDMAEMA) with styrene (St) in solution

in which the salts are butyl bromide salt(MABB) and ethyl bromidesalt (MAEB)

respectively. Variousexperimental parametersofthe copolymerization andthe solubility ofcopolymers were studiedin detail. The structure ofcopolymers was determined by the spectra of IR

1H-NMR and 13C-NMR

which are perfectly consistent with the expected macro-molecular structure of the random copolymer with both hydrophobic and hydrophilic chain units.Finally

monomer reactivity ratios of MAABB/St and MAEB/St were obtained

rMABB=0.44

rSt=0.15;rMAEB=0.66

rSt=0.36

using YBR method.