摘要
Poly（acrylamide-co-acrylic acid） nanocomposite physical （P（AAm-co-AAc）NCP） hydrogels have been prepared through the in situ free radical solution polymerization based on a ＂single network, dual cross-linkings＂ strategy. The P（AAm-co-AAc） NCP hydrogels are composed of nanobrushes of P（AAm-co-AAc） chains grafted on the surface of vinyl- hybrid silica nanoparticles （VSNPs）. In the hydrogel system, the VSNPs act as the ＂analogous chemical cross-linking points＂ once the hydrogen bonds formed between the P（AAm-co-AAc） chains of the nanobrushes, thus leading to the fabrication of high-strength P（AAm-co-AAc） NCP hydrogels. Compared with conventional thermosensitive P（AAm-co-AAc） hydrogels, the P（AAm-co-AAc） NCP hydrogels have a broader range of phase transition temperature, which can be adjusted by altering the monomer ratio, the VSNPs concentration, the addition of urea and N,N-dimethylacrylamide （DMAAm）. At the same time, the mechanical properties of the P（AAm-co-AAc） NCP hydrogels have been improved significantly by the introduction of VSNPs. Furthermore, both the phase transition and the tensile strength of the P（AAm-co-AAc） NCP hydrogels are largely influenced when Fe3＋ ions are introduced as the ionic crosslinkers into the hydrogel networks.
Poly（acrylamide-co-acrylic acid） nanocomposite physical （P（AAm-co-AAc）NCP） hydrogels have been prepared through the in situ free radical solution polymerization based on a ＂single network, dual cross-linkings＂ strategy. The P（AAm-co-AAc） NCP hydrogels are composed of nanobrushes of P（AAm-co-AAc） chains grafted on the surface of vinyl- hybrid silica nanoparticles （VSNPs）. In the hydrogel system, the VSNPs act as the ＂analogous chemical cross-linking points＂ once the hydrogen bonds formed between the P（AAm-co-AAc） chains of the nanobrushes, thus leading to the fabrication of high-strength P（AAm-co-AAc） NCP hydrogels. Compared with conventional thermosensitive P（AAm-co-AAc） hydrogels, the P（AAm-co-AAc） NCP hydrogels have a broader range of phase transition temperature, which can be adjusted by altering the monomer ratio, the VSNPs concentration, the addition of urea and N,N-dimethylacrylamide （DMAAm）. At the same time, the mechanical properties of the P（AAm-co-AAc） NCP hydrogels have been improved significantly by the introduction of VSNPs. Furthermore, both the phase transition and the tensile strength of the P（AAm-co-AAc） NCP hydrogels are largely influenced when Fe3＋ ions are introduced as the ionic crosslinkers into the hydrogel networks.
基金
financially supported by the National Nature Science Foundation of China(No.21474058)
State Key Laboratory for Modification of Chemical Fibers and Polymer Materials,Donghua University(No.LK1404)
Tsinghua University Scientific Research Project(No.2014Z22069)
