Wenxu Zhang,Xuyang Mu,Yan Xu,Sijie Li,Xiaoming Liu,Ziqiang Lei
Temperature/pH-responsive hydrogels are one of the most studied environmental-responsive hydrogels, with sensitivity and rapid response being the sought-after properties, while sensitivity and reusability are generally poor. This study prepared a hydrogel with a temperature/pH-responsive core-shell structure by static template polymerization, using the temperature-sensitive monomer dimethylaminoethyl methacrylate polymerized with 2-acrylamide-2-methylpropanesulfonic acid as the temperature-sensitive shell and popcorn with acrylic acid as the pH-responsive core-layer hydrogel. The chemical structure, thermal stability, and morphology of the core-shell structure hydrogels were characterized by Infrared spectroscopy (FTIR), X-ray diffraction (XRD), Brunauer-Emmett-Teller surface (BET), Scanning electron microscopy (SEM), Atomic force microscopy (AFM) and Thermogravimetric analysis (TG), respectively. The pH responsiveness well as the temperature responsiveness of the shell structure was tested. The results showed that the lowest critical solution temperature (LCST) of the core-shell hydrogel is 43 ℃, with good temperature responsiveness in the range of 25–55 ℃, pH responsiveness from pH= 4 to pH= 13, and a short response time. From SEM, AFM, and BET, it can be concluded that the hydrogel has a rough surface and pore structure with a root mean square roughness value of 0.787 nm, a specific surface area of 1.3381 m²/g, and an average pore size of 4.0911 nm. FTIR and XRD can show that popcorn (PCP) is well-doped in the core-shell structure hydrogel, which also proves the existence of the core-shell structure. The design of the core-shell structure enhanced the stability performance of the shell temperature-sensitive hydrogel so that the retention rate of the sample was still 37% at 800 °C, and the water retention rate was still 80.7% after repeated immersion in distilled water 7 times, which has good prospects for agricultural and pharmaceutical applications.
Rational structure design of semiconductor photocatalysts is meaningful to enhance their sunlight-driven hydrogen-evolution performance. Herein, we present a facile approach to prepare Cd1−xZnxS nanopopcorns with zinc blende/wurtzite phase junctions by using excess thioacetamide (TAA). The as-obtained Cd1−xZnxS samples were used for visible-light photocatalytic H2 evolution without a co-catalyst. The H2-evolution activity reaches 282.14 μmol h−1 mg−1, which is ca. 12 fold higher than that of Cd0.5Zn0.5S prepared with an equivalent dose of TAA. Meanwhile, an apparent quantum yield of 64.4% at 420 nm was achieved. Results demonstrated that the Cd1−xZnxS samples synthesized by using excess TAA improve light absorption and hydrophilicity, which is helpful for the photocatalytic reaction. Moreover, the existence of type-II ZB/WZ phase junctions promotes the separation and migration of photoinduced electron–hole pairs. This work provides a novel idea for the rational design of efficient Cd1−xZnxS-based photocatalysts.
Abstract o -Vanillin is a natural product that has been widely applied in the food and pharmaceutical industries. In this study, we determined that o -vanillin can strongly inhibit the growth of Aspergillus flavus mycelia. However, the inhibition mechanism of o -vanillin is still elusive. The ultrastructural morphology of mycelia was injured, and the cell walls were destroyed. The OH functional groups on cell walls were altered, and the content of protein in mycelial cell walls was reduced by o -vanillin. The content of β-1,3-glucan in cell walls was significantly ( P < 0.05) reduced by o -vanillin in a dose-dependent manner, while chitin was not markedly affected. Moreover, o -vanillin led to an increase in the permeability of cell membranes. o -Vanillin also exhibited a promising antifungal effect on contaminated corn kernels. Therefore, o -vanillin inhibited the growth of mycelia by disrupting the integrity of cell walls and cell membranes. This study not only sheds light on the antifungal mechanism of o -vanillin but also indicates that it is a promising agent for the control of A. flavus infection. Key points o -Vanillin has strong inhibitory effects on A. flavus. o -Vanillin destroyed the integrity of cell walls and cell membranes. o -Vanillin could effectively inhibit the growth of A. flavus on corn kernels.
危险品化学品经营许可证（带存储）