To overcome limitations of single-trigger self-healing systems, this study developed microcapsules (MCs) responsive to both mechanical stress and chloride ions for marine concrete repair. Ethyl cellulose/nano-silica shells encapsulating epoxy resin were synthesized via solvent evaporation method, with PbSO 4 embedded for chloride activation. MCs exhibited optimal size (70–120 μm), thermal stability (>190 °C), and homogeneous PbSO 4 distribution. Increasing PbSO 4 content enhanced chloride responsiveness, forming pores that released healing agent via osmotic pressure, while improving MC stiffness. Additionally, the self-healing mortars demonstrate notable strength recovery, with the highest healing rate of 126.30 % under standard curing and 114.50 % under seawater curing, reflecting the MCs' robust performance in aggressive environments. Cracks up to 229.7 μm width were effectively healed within 7 days, with healing efficiency positively correlating with PbSO 4 content. The porosity reduction rate rose with the increase in PbSO4 dosage, reducing porosity by 9.42 %–26.71 % post-healing. Additionally, MC significantly enhanced the chloride ion permeability resistance of self-healing mortars, achieving a reduction rate of 67.37 %–84.90 %. This d ual-trigger system provides targeted, efficient self-healing for marine concrete infrastructure, significantly enhancing durability.
Kaining Zhang,Hao Sun,Long Wei,Rui Hu,Hao Liu,Yongchao Lai,Xun Li
Glutathione (GSH) levels have been well validated to correlate with a variety of physiological and pathological conditions, such as malignancy, cardiovascular disease and aging, making the development of accurate, robust and sensitive GSH detection methods highly desirable. In this study, a novel metal–organic framework (MOF-Fe(DTNB))-based colorimetric method with a favorable dual-triggering function was proposed. MOF-Fe(DTNB) exhibits high peroxidase activity, which can catalyze the oxidation of colorless 3,3′,5,5′-tetramethylbenzidine (TMB) to blue ox-TMB by hydrogen peroxide (H 2 O 2 ). This oxidation process of TMB can be inhibited not only by the reducing action of GSH, but also by the thiol exchange reaction between DTNB and GSH, in which the disulfide bond of DTNB in MOF-Fe(DTNB) is cleaved. Thus, with this dual triggering mechanism, the GSH concentration can be robustly measured in the MOF-Fe(DTNB)-derived colorimetric strategy. Significantly, this method is accurate (RSD < 6 %), selective and sensitive in biological plasma samples, with satisfactory recovery rates (96.7–103.3 %). It requires less instrumentation and has less interference from other substances. The linear range of the method is 0–80 µM, and the detection limit is as low as 0.28 µM. This dual-triggering MOF-Fe(DTNB)-derived colorimetric strategy has greatly simplified the GSH detection processes with improved accuracy, in both acidic and basic environments, which has potent applications in biochemical analysis and point-of-care testing.
危险品化学品经营许可证（带存储）