Tough, High stretched, Self-healing C-dots/Hydrophobically Associated Composited Hydrogels and Their Use for a Fluorescence Sensing Platform

In this paper, about 3.5 nm spherical carbon nanodots (C-dots) were prepared through simple hydrothermal method, then they were introduced into the hydrophobically associated (HA) hydrogels. A new class of double physically crosslinked hydrogels (HCD hydrogels) were successfully prepared. C-dots act as physical crosslinker in HA physically cross-linked PAM network, and the hydrogen bond interaction between C-dots and PAM chains endows the hydrogel with extraordinarily mechanical, high stretched and self-healing properties. Moreover, introduction of C-dots gives HCD hydrogels excellent fluorescence properties and good photostability. The location of emision-wavelength of HCD hydrogel was independent of excitation-wavelength, while the fluorescenceintensity depended on excitation-wavelength, and increased linearly with the increased concentration of C-dots. The sensing HCD hydrogel platform based upon ROS of detecting H2O2 was also explored. ROS formed by decomposition of H2O2 induced fluorescence quench of hydrogels. The fluorescence intensity ratio (I-0/I) of the H2O2-HCD at 550 nm correlated linearly with the concentration of H2O2 in the range of 0.01-25 M. Impressively, this fluorescence sensor exhibited high sensitivity, simplicity, cost-efficiency and broad applicability. Consequently our study demonstrates a general approach to prepare the robust and self-healing hydrogels which have application potential in sensing fields.