Abstract
pH-/temperature-sensitive ampholytic poly(N-isopropylacrylamide) (PNIPAAm) hydrogels containing N-[3-(dimethylamino)propyl]methacrylamide-itaconic acid (DMAPMAAm-IA) and DMAPMAAm-AMPS (2-acrylamido-2-methylpropane sulfonic acid) comonomer pairs have been designed and then synthesized. The results showed that (i) disk diameters and transparencies in the range of pH 2–12 increased only with increasing content of AMPS in the ampholytic NIPAAm/DMAPMAAm/AMPS hydrogels containing 10.0 mol % of DMAPMAAm + AMPS mixtures; (ii) maximum compressive strengths of NIPAAm/IA (62.5 ± 10.0 kPa) was higher than NIPAAm/AMPS (26.9 ± 1.1 kPa) hydrogels in DDW at 37 °C. (iii) In case of DFNa release, the decreasing values of n (≈0.30–0.50) indicated that ampholytic PNIPAAm hydrogels served as diffusion barrier.
Graphical Abstract
Abbreviations: NIPAAm/DMAPMAAm: copolymer of NIPAAm with DMAPMAAm; NIPAAm/AMPS: copolymer of NIPAAm with AMPS; NIPAAm/IA: copolymer of NIPAAm with IA; NIPAAm/DMAPMAAm/AMPS: terpolymer of NIPAAm containing DMAPMAAm and AMPS; NIPAAm/DMAPMAAm/IA: terpolymer of NIPAAm containing DMAPMAAm and IA.
Acknowledgements
We thank Dr. Gökhan Göksu for guidance on MATLABTM calculations.
Disclosure statement
No potential conflict of interest was reported by the authors.