An environment-friendly fluorescent nano-hybrid hydrogel has been synthesized successfully, from cellulose nanocrystal (CNC), acrylic acid (AA) and phosphorescent Eu²⁺/Dy³⁺ doped SrAl₂O₄ via free radical polymerization. The hydrogel network matrix fixed Eu²⁺/Dy³⁺ doped SrAl₂O₄ nanoparticles by polymer chains with coordinate bonds that prevented particles from aggregating and quenching in water. The fluorescent nano-hybrid hydrogel exhibited extremely high water absorption of which the swelling ratio in distilled water and NaCl salt solution were respectively of 323.35 g/g and 32.65 g/g. Furthermore, the hydrogel displayed excellent water retention property that can keep half of the moisture even exposed to 80 °C for 210 min. Besides, the hydrogel had bright green fluorescence under the sunlight or ultraviolet excitation, and the fluorescence intensity was up to 125477 after swelling 50 times in water. The time-resolved photoluminescence (TRPL) afterglow decay examination showed that the fluorescent emission persisted for 4 h after hydrogels excited at 368 nm wavelength UV-light for 10 min. The fluorescence intensity behaved significant linear relationship with the swelling ratio. As a result, these hydrogels were considered as promising candidates for the preparation of stable and sensitive sensor materials in green water detection.

中文翻译：

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制备用于水检测的荧光和吸收性纳米杂化水凝胶的绿色途径。

通过纤维素纳米晶体（CNC），丙烯酸（AA）和磷光掺杂Eu ²⁺ / Dy ^3+的SrAl ₂ O _4的自由基聚合反应，成功合成了一种环保型荧光纳米混合水凝胶。水凝胶网络基质固定的Eu ²⁺ / Dy ³⁺掺杂SrAl ₂ O ₄通过具有配位键的聚合物链形成的纳米颗粒，可防止颗粒在水中聚集和淬灭。荧光纳米混合水凝胶显示出极高的吸水率，其在蒸馏水和NaCl盐溶液中的溶胀率分别为323.35g / g和32.65g / g。此外，水凝胶显示出优异的保水性能，即使将其暴露在80°C下210分钟也可以保持一半的水分。此外，该水凝胶在日光或紫外线激发下具有亮绿色的荧光，在水中溶胀50倍后，荧光强度高达125477。时间分辨光致发光（TRPL）余辉衰减检查表明，水凝胶在368 nm波长的紫外线下激发10分钟后，荧光发射持续了4 h。荧光强度与溶胀率呈显着的线性关系。结果，这些水凝胶被认为是在绿水检测中制备稳定和敏感的传感器材料的有前途的候选物。