In this research, the effects of fresh and oxidized MXene on the surface, adhesion, and corrosion-resistant properties of waterborne epoxy coatings are considered. The oxidized MXene is prepared through storage of fresh MXene nanosheets in an open vial for 1 month. The results confirm that the waterborne epoxy coating loaded with silane functionalized fresh MXene nanosheets (epoxy/F-MXene) has significantly higher barrier performance and anti-corrosion behavior than the sample modified with silane functionalized oxidized MXene nanosheets (epoxy/F-O-MXene). Indeed, the F-MXene nanosheets (with defect-free and large two dimensional morphology) are able to effectively inhibit the path of corrosive media as well as increment the epoxy matrix compactness compared to the F-O-MXene (with broken nanosheet morphology composed of TiO 2 nanoparticles) due to rapid oxidation of the MXene nanosheets in the environment. Besides, the epoxy/F-MXene nanocomposite coating has slightly higher water contact angle and adhesion strength to the metallic substrate compared to the epoxy/F-O-MXene. The results of this research clearly reveal the importance of preventing MXene oxidation before application as nanofiller in the polymer coatings.
Junyong Sun,Like Chen,Xin Zhang,Xian Liu,Can Wu,Tian Gan
Herein, we designed and fabricated hollow N -doped carbon polyhedrons with atomically dispersed Zn species (Zn@HNCPs) through a topo-conversion strategy by utilising metal–organic frameworks as precursors. Zn@HNCPs achieved efficient electrocatalytic oxidation of sulfaguanidine (SG) and phthalyl sulfacetamide (PSA) sulfonamides through the high intrinsic catalytic activity of the Zn-N 4 sites and excellent diffusion from the hollow porous nanostructures. The combination of the novel Zn@HNCPs with two-dimensional Ti 3 C 2 T x MXene nanosheets resulted in improved synergistic electrocatalytic performance for the simultaneous monitoring of SG and PSA. Therefore, the detection limit of SG for this technique is much lower than those of other reported techniques; to the best of our knowledge, this is the first detection approach for PSA. Moreover, these electrocatalysts show promise for the quantification of SG and PSA in aquatic products. Our insights and findings can serve as guidelines for the development of highly active electrocatalysts for application in next-generation food analysis sensors.
Jingwen He,Ze Wu,Bingjue Li,Youqiang Xing,Peng Huang,Lei Liu
Untethered intelligent soft robots capable of autonomous, continuous, directional, and fast movements under external stimuli have great potential in environmental, industrial, military, and medical fields. This paper used an unconventional dual-flow filtration method to prepare a laterally heterogeneous MXene-NiFe 2 O 4 /Polycarbonate bilayer membrane. Based on this, a one-piece untethered soft crawling robot with multi-stimulus synergistic control is developed, which can achieve relatively fast crawling up to 3.77 mm/s and directional turning locomotion. In addition, a cross-shaped robot that can realize biaxial flipping locomotion is developed by using the inverse snapping property of the polycarbonate films under light and humidity excitation. The preparation method has also been extended to unconventional multi-flow filtration and applied to bionic flowers and asymmetric grippers with biological gradients. This work provides an effective way for designing soft crawling robots with fast actuation performance and adjustable trajectories that can be used in areas such as bionic soft robots and biomedical systems.
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