Controlled tuning of LCST based on poly (N-isopropylacrylamide)/Hydroxypropyl cellulose temperature-sensitive hydrogel by electron beam pre-radiation method

As a temperature-sensitive-discoloration hydrogel based on NIPAAm/HHPC was fabricated via two steps of electron beam radiation. Small nanomaterial such as GO and Fe 2 O 3 were also added severally into the system of hydrogel as chromogenic agent. Different colors can be displayed in nanocomposite hydrogel system at the low, medium and high temperature respectively. The LCST of hydrogel system can be also adjusted precisely by the changes of irradiation dose of the prepolymer and composition ratio. Experimental results showed that the hydrogel can be changed quickly itself color in its near LCST. The microstructure and composition of nanocomposite hydrogel were characterized further by NMR, FTIR, TG, DSC, XRD, FE-SEM and XPS so as to reveal the mechanism of temperature-sensitive- discoloration. The novel NIPAAm/HHPC-based nanocomposite hydrogel is suitable especially to indicate different fever temperatures for fever patients and can be expected to as a new type of temperature-sensitive sensor and replace the traditional clinical thermometer. Graphical abstract ( A ) SEM images of different hydrogels (previous row). ( B ) The reversible temperature-sensitive-discoloration process of different hydrogels ( bottom left ). ( C ) DSC thermograms of different hydrogels ( bottom right ).