The effects of L-phenylalanine (L-Phe) on the synthesis of poly(N

N-methylenebisacrylamide-co-4-vinylpyridine) (poly(Bis-co-4-VP)) (micro)gels by -ray irradiation were studied. The addition of L-Phe could not only decrease the gelation dose (Dg) of the synthesis obviously

but also transform the morphology of copolymer from microgel to gel. In addition

the swelling ability of the (micro)gels was also affected in the presence of L-Phe. The decrease of Dg was ascribed to the effect of pH

while the transformation of the morphology was ascribed to the effect of L-Phe on the stability of the poly(Bis-co-4-VP) microgel. Such an effect was confirmed further as compared with the effects of L-alanine

L-glutamic acid

L-arginine

sulfuric acid and aqueous ammonia.