Atom transfer radical polymerization of iso-butyl methacrylate in microemulsion with cationic and non-ionic emulsifiers

Direct atom transfer radical polymerization (ATRP) of iso-butyl methacrylate in microemulsion has been performed successfully for the first time. ATRP was performed at 40 degrees C with different emulsifier systems: i) the cationic emulsifier n-tetradecyltrimethylammonium bromide (TTAB); and ii) mixed emulsifier systems based on TTAB and the non-ionic emulsifiers Emulgen 911 or Emulgen 931. All polymerizations proceeded in a controlled/living fashion, and the microemulsions were transparent with particle diameters less than 15 nm. The emulsifier system TTAB/Emulgen 911 exhibited better control than TTAB only. This is proposed to be caused by complex formation between Emulgen 911 in the organic phase and CuBr2 (the deactivator), thus reducing the extent of exit of CuBr2 to the aqueous phase.. The more hydrophilic Emulgen 931 did not lead to improved control.