A novel method to prepare temperature/pH-sensitive poly(N,N-diethylacrylamide-coacrylic acid) hydrogels with rapid swelling/deswelling behaviors

摘要

Fast responsive temperature- and pH-sensitive hydrogels of poly(N,N-diethylacrylamide-co-acrylic acid) (P(DEAco-AA)) have been synthesized successfully by a two-step procedure, in which the initial polymerization was conducted at constant temperature for 15 min, followed by further polymerization at -30℃ for 12 hr. Swelling studies showed that hydrogels thus prepared had almost the same temperature and pH sensitivity compared with the conventional ones (polymerized at 24℃ for 12 hr). However, hydrogels thus prepared had faster swelling/deswelling rates in distilled water than the conventional ones, and their deswelling rates in low pH buffer solutions were also faster than the conventional ones. These improved properties were attributed to the porous network structure, which was confirmed by the results of scanning electron microscopy.