Rapid deswelling of semi-IPNs with nanosized tracts in response to pH and temperature.
Porous linear-polymer penetrating networks (semi-IPNs) were prepared by the radical polymerization of acrylic acid (AAc) inside porous poly(N-isopropylacrylamide) hydrogels with "nano-sized tract networks (nano-tracts)." The deswelling behavior was investigated by measuring the time course of the swelling ratio change of the semi-IPNs just after the temperature or pH was changed. Although the incorporation of PAAc linear chains into the PNIPAAm hydrogel networks should facilitate deswelling, nonporous semi-IPNs showed only a slow thermoresponse under low pH conditions, and a slow pH-response under a high temperature. On the other hand, the porous semi-IPNs showed a rapid deswelling in response to either a change in pH or temperature, regardless of the environment, presumably due to the nano-tracts through which the water was rapidly released from the hydrogel without any interference by network shrinking. The novel network design of these nano-tracted semi-IPNs may be useful for high performance, dual molecule-release functions.
Asoh
Taka-Aki
TA
Department of Applied Chemistry, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita 565-0871, Japan; Department of Nanostructured and Advanced Materials, Graduate School of Science and Engineering, Kagoshima University, 1-21-40 Korimoto, Kagoshima 890-0065, Japan.
Kaneko
Tatsuo
T
Department of Applied Chemistry, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita 565-0871, Japan.
Matsusaki
Michiya
M
Department of Applied Chemistry, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita 565-0871, Japan.
Akashi
Mitsuru
M
Department of Applied Chemistry, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita 565-0871, Japan. Electronic address: akashi@chem.eng.osaka-u.ac.jp.
D000180:Acrylic Resins / Q000737:chemistry; D000465:Algorithms; D002152:Calorimetry, Differential Scanning; D005079:Excipients; D020100:Hydrogels; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D049329:Nanostructures / Q000737:chemistry*; D010316:Particle Size; D013696:Temperature
D000180:Acrylic Resins; D005079:Excipients; D020100:Hydrogels; C052970:poly-N-isopropylacrylamide