Nanocomposite hydrogels with rapid thermal-responsibility by using surfactant detergent as template

Abstract

To improve thermal-responsibility of poly N-isopropylacrylamide/inorganic hectorite hydrogels, inorganic hectorite severed as physical cross-linker, a kind of nonionic surfactant detergent polyoxyethylene 20 cetyl ether (POECE) was used as template to prepare nanostructured hydrogels (THPN hydrogels). The structure, morphology, temperature-sensitivity and swelling behavior of THPN hydrogels were characterized. Comparing to pure PNIPA hydrogel, THPN hydrogels exhibited higher swelling ratio as well as faster response rate. In the case of temperature-sensitivity, the volume phase transition temperature (VPTT) of THPN hydrogels was between 32 and 34°C, slightly different from pure PNIPA hydrogel. The results of FTIR, 1H NMR and TGA showed that a small amount of POECE adsorbed onto surface of hectorite, and it is maybe one of the reasons of higher swelling ratio and faster response rate. SEM and FESEM images showed that THPN hydrogels have more regular and smoother pore structure due to the POECE which severed as the effect of POECE template, and the hectorite dispersed homogeneously in THPN hydrogels regardless of adsorption of POECE, respectively.