Abstract
When poly(acrylic acid) (AA)-1,8-diazabicyclo-[5,4,0]-7-undecene salt (DAA) was placed in NMP containing excess amounts of alkylamine and TPP, the amidation from the outside took place selectively to give the corresponding poly(N-alkylacrylamide) gel containing C3 alkyl chain through a DAA-poly(N-alkylacrylamide) type gel capsule consisting of a hydrophilic unreacted core part and amidated shell layer. The amidation proceeded according to a similar reaction mechanism to the unreacted-core model. Thermal properties of the obtained poly(N-alkylacrylamide) gels such as deswelling behavior and equilibrium swelling ratio in water as a function of temperature were measured. The release of Methyl Orange from poly(N-alkylacrylamide) gel and the gel capsule was also studied. AA-poly(N-alkylacrylamide) type gel capsules containing an AA core part and thermosensitive poly(N-alkylacrylamide) shell layer, which was prepared from the neutralization of DAA-poly(N-alkylacrylamide) type gel capsules, showed on-off chemical release in response to stepwise temperature changes cross the LCST.
