Preparation and properties of GQDs-TiO2/polyacrylamide fluorescent hydrogel
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摘要: 通过将原位溶胶-凝胶法和自由基聚合法巧妙相结合制备了一种坚固、荧光的杂化水凝胶石墨烯量子点-TiO2/聚丙烯酰胺(GQDs-TiO2/PAM)。在该杂化水凝胶中,同时充当多功能交联剂和纳米填料的TiO2和GQDs粒子与水凝胶网络中的亲水基团通过氢键等非共价键牢固地结合。PAM、TiO2和GQDs之间的强非共价键作用赋予该凝胶优异的力学性能。GQDs-TiO2/PAM (0.5wt%GQDs)水凝胶的断裂伸长率和抗拉强度分别高达2412%和181 kPa,为TiO2/PAM水凝胶的1.78和1.13倍。另外,GQDs的引入还赋予该复合水凝胶特殊的荧光性能,它能够在365 nm紫外光照射下发出明显的蓝色荧光。因此,该水凝胶在生物医药、重金属离子检测、荧光探针等领域有很大发展潜力。Abstract: A kind of strong and fluorescent hybrid hydrogel graphene quantum dots (GQDs)-TiO2/polyacrylamide (PAM) hydrogel was prepared via a simultaneous in-situ sol-gel method and free radical polymerization. In the hybrid hydrogel, TiO2 and GQDs particles, which served as multifunctional crosslinkers and nano-fillers, were firmly bound to hydrophilic groups in the hydrogel network through noncovalent bonds such as hydrogen bonds. The strong non-covalent interactions among PAM, TiO2 and GQDs endowed the gel with excellent mechanical properties. The elongation at break and tensile strength of GQDs-TiO2/PAM (0.5wt%GQDs) hybrid hydrogels are 2412% and 181 kPa, respectively, which are 1.78 and 1.13 times that of TiO2/PAM hydrogels. In addition, the introduction of GQDs also endowed the hybrid hydrogels with special fluorescence properties, which could emit obvious blue fluorescence under 365 nm ultraviolet light. Therefore, the hydrogel has great development potential in biomedicine, heavy metal ion detection, fluorescence probes, and other fields.
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Key words:
- GQDs /
- TiO2 /
- hybrid hydrogel /
- mechanical properties /
- fluorescence
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图 1 (a) GQDs-TiO2/聚丙烯酰胺(PAM)杂化水凝胶的形成过程示意图;TiO2溶胶(b)、AM-TiO2分散液(c)、AM-GQDs-TiO2分散液(d)及水凝胶(e)的照片
Figure 1. (a) Schematic diagram for the preparation of GQDs-TiO2/polyacrylamide (PAM) hybrid hydrogel; Photographs of TiO2 hydrosol (b), AM-TiO2 dispersion (c), AM-GQDs-TiO2 dispersion (d) and hydrogel (e)
图 8 TiO2/PAM、GQDs/PAM和GQDs-TiO2/PAM水凝胶薄膜覆盖的不同浓度亚甲基蓝溶液 (0.01wt‰和0.004wt‰)紫外光照前后的吸收光谱
Figure 8. Absorption spectra of methylene blue solutions (0.01wt‰ and 0.004wt‰) with different concentrations covered by TiO2/PAM, GQDs/PAM and GQDs-TiO2/PAM hydrogel films before and after ultraviolet irradiation, respectively
表 1 不同石墨烯量子点(GQDs)含量水凝胶的配方
Table 1. Formula of hydrogels with different contents of graphene quantum dot (GQDs)
Hydrogel TEOA/g TBOT/µL AM/g GQDs/wt% BIS (0.1wt%, mL) APS/g PAM — — 2.5 — 2 0.08 GQDs/PAM — — 2.5 1 2 0.08 TiO2/PAM 0.1756 200 2.5 — 2 0.08 GQDs-TiO2/PAM 0.1756 200 2.5 0.5 2 0.08 GQDs-TiO2/PAM 0.1756 200 2.5 1 2 0.08 GQDs-TiO2/PAM 0.1756 200 2.5 3 2 0.08 GQDs-TiO2/PAM 0.1756 200 2.5 5 2 0.08 Notes: TEOA—Triethanolamine; TBOT—Tetrabutyl titanate; AM—Acrylamide; BIS—N, N'-methylenebis(2-propenamide); APS—Ammo-nium persulphate; PAM—Polyacrylamide. -
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