2.1. Materials
Acrylamide (Am) (Shanghai LuNiao Co.) was
re-crystallized twice from chloroform and then
vacuum dried. The cross-linking agent N; N0-
methylene bis acrylamide (MBA) (Shanghai Chem
Reagent Co.) was re-crystallized from acetone and
vacuum dried. FeCl2 4H2O and FeCl3 6H2O
(Merck), polymethacrylic acid (Henkel co.), cyclohexane
(Shanghai FeiDa Trade Company), ammonia
(Shanghai Chem. Reagent Co.) and Span
80 (Sigma Chemical Co.) were all used as supplied.
Hydrophobic initiator 2,20-azobis (isobutyronitrile)
(AIBN) (Aldrich) was recrystallized from
ethanol and vacuum dried. In this study, only
distilled water was used.