N-chlorinated poly(N-isopropylacrylamide) microgels.
The treatment of poly(N-isopropylacrylamide) (PNIPAM) microgels with aqueous bleach (NaClO) at pH 10.5 resulted in the partial conversion of the amide hydrogen to the corresponding chloramide. N-Chlorinated microgels poly(NIPAM-co-NIPAMCl) are more hydrophobic than the parent PNIPAM microgels. Thus, the volume phase transition temperature decreases with increasing chlorination. During chlorination, the microgels coagulate once they undergo a volume phase transition. The chlorination reaction stops once the microgels dehydrate and coagulate, presumably as a result of the decreased diffusion rate of the ClO(-) anion into the microgels. The microgels are reversibly dechlorinated by glutathione (GSH), first giving PNIPAM shell + poly(NIPAM-co-NIPAMCl) core microgels. Because GSH is an important redox actor in biological cells, this work suggests that chlorinated microgels may be employed to deliver active chlorine to targeted cells.
Department of Chemical Engineering, McMaster University , 1280 Main Street, West Hamilton, Ontario, Canada L8S 4L7.
Zuohe
Z
Wang
Wing Yan
WY
Lam
Robert
R
Pelton