To minimize the internal polarization concentration (ICP) in FO process and improve the structural stability of thin film composite (TFC) forward osmosis (FO) membrane, a reactable hydrophilic ...nanofiber substrate was prepared by vacuum filtrating an interlayer composed of polydopamine nanoparticles (PDA NPs) onto an electrospun polyacrylonitrile nanofiber substrate. Then a TFC FO membrane with dense selective layer, low structure parameter, high water permeability and low salt permeability was prepared by the interfacial polymerization thereon. According to the T-peel test, the resulting TFC FO membrane showed greatly improved adhesion strength between selective layer and substrate due to the chemical bonding and entanglement between polyamides and the PDA NPs, and the strong adhesion between PDA NPs and the nanofibers. The ICP in FO process for the resulting membranes were minimized due to the application of the nanofiber substrates with low structure parameter (in the range of 290 ± 36 μm–354 ± 20 μm). These FO membranes performed well in the heavy metal ions contained water treatment, showed 1–2 times higher water flux (29.2 ± 0.3 L/m2h) compared with commercial TFC membrane (HTI-TFC) and high heavy metal ions rejection (99.5% ± 0.4%, 99.1% ± 0.5%, 98.1% ± 0.7% for Cr3+, Cu2+ and Ni2+, respectively) when using 2.0 M NaCl as draw solution. The findings provide the pathway for the design of nanofiber based FO membrane with improved structure stability and high performance by interfacial polymerization.
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•PDA NPs composed interlayer was filtrated onto the nanofiber substrate.•TFC FO membrane was prepared on the PDA NPs modified nanofiber substrate.•Adhesion strength was greatly improved by using the PDA NPs modified substrate.•The ICP in FO process was minimized by using the prepared FO membrane.•The prepared FO membrane performed well in heavy metal ions removal.
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•EPL can notably improve the antifungal ability of a SM-based adhesive.•The modified SM adhesives had no significant structural change after treatment.•The modified SM adhesives still ...exhibited a good thermal stability after treatment.•The plywood bonded by SM/EPL adhesive increased to 1.10 MPa after treatment.
Soy protein adhesive is readily deteriorated by microorganism, which greatly limits its practical application in the plywood industry. In this research, a soybean meal (SM)-based adhesive with excellent antifungal property, thermal stability and bonding strength was successfully prepared using epoxy polymer of lignin (EPL) as a crosslinking agent. The results confirmed that the lignin-based polymer can notably improve the antifungal ability of a soy-based adhesive. The initial microbial attack of SM/EPL adhesive was better than that of pure SM adhesive (on 3rd day), delaying to 22th day under high humidity conditions. Moreover, the fungal growth on the modified SM adhesives was Aspergillus flavus. The mycelia only existed on the surface of the modified SM adhesives, but not observed inside, and the modified SM adhesives had no significant structural change, and still exhibited a good thermal stability. Furthermore, no microbial attack observed on the surface and glueline of plywood bonded by modified SM adhesives. These results may be due to its phenolic hydroxyl groups and dense network structure hindering the erosion of fungi. On the other hand, the wet shear strength of SM/EPL adhesive reached 1.02 MPa, which was a 363.6 % increase compared with the neat SM adhesive (0.22 MPa). Also, the adhesion strength still met the requirements of interior-use plywood (≥ 0.7 MPa) after being treated for a month. This work not only highlights the application potential of lignin-based polymer as an effective antifungal material, but also broadens the application of soy-based adhesives.
Carbon nanotubes (CNTs) demonstrate the potential to improve the tribological properties of nanocomposite coatings. Herein, CNTs/Ni composite coatings were quickly fabricated by the direct current ...(DC) electrodeposition. The adhesion strength was estimated by the scratch test incorporation with an acoustic emissive signal. Much attention was paid on the self-lubricity of the CNTs/Ni composite coating under severe conditions. Results indicated that presence of CNTs enhanced the adhesion strength of the pure Ni coating. Notably, CNTs contributed towards 54.5 % of friction reduction in comparison to the pure Ni coating at dry friction. The improvement of tribological properties was attributed to that under high contact stress the embedded CNTs were crushed to tiny lubricating particles and produced protective film on rubbing surfaces.
To improve the degradation properties of magnesium (Mg) alloy-based temporary implants, a durable polymer coating with high adhesion and desirable anti-corrosion performance is designed in this work. ...The biodegradable poly(3-hydroxybutyrate) (PHB) with high crystallinity (>60 %) and low glass transition temperature (Tg < 5 °C) is conducted as the protective coating for Mg alloy. The hydrogen evolution rate decreases by 2.56 times with the protection of the PHB coating, while the maximum concentrations (Cmax) of Na+ and Cl− ions penetrated across the PHB film are <0.1 % and 10 % of their total concentrations respectively. Furthermore, a simple approach through the network interdiffusion, hydrogen bonding, and chemical cross-linking is performed to improve the adhesion from 0.19 to 8.36 MPa. The modified PHB coated Mg alloy with a strong interface shows excellent corrosion resistance even after 168 h immersion. The design principle for durable polymer coatings is proposed based on the above results. Moreover, the interfacial bonding is identified by the Density Functional Theory (DFT) computational method. This study demonstrates the prepared PHB coating could act as an ion barrier to supply efficient protection for Mg alloys in vitro and enriches our understanding on the structure-property-performance relationship of polymer coatings.
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•A durable polymer coating with high adhesion and desirable anti-corrosion performance is designed.•The design principle related to crystallinity, glass transition temperature and adhesion has been proposed.•Density Functional Theory (DFT) calculations are carried out to estimate the interactions between PHB and GPTMS.•The molecular structure-property-performance relationship of PHB coatings is studied systematically.•The penetration behaviors of Na+ and Cl− ions through PHB film are monitored on the custom in situ apparatus.
A detailed theoretical investigation of the interface binding characteristics of Cu(111)/WC(0001) interfaces is studied by first-principles method. The calculation results of the physical properties ...of Cu and W verify the reliability of our calculation settings. The surface energy calculation results show that the surface of W-termination WC(0001) is the most stable of the two WC(0001) surfaces. The adhesion work of eight W(C)-terminated Cu(111)/WC(0001) interfaces and the interface energy and electronic structures of six stable structures are studied. The results show that bridge site stack interface can be transformed into fcc site stack interface. Among all interface structures, the C-fcc-Cu has the maximum interface adhesion work, while W-hcp-Cu has the minimum interface energy. Analysis of electronic structure reveals that the dominant interfacial bonding is the Cu–W covalent bond and Cu–C covalent bond for the W-termination and C-termination Cu(111)/WC(0001) interface, respectively.
•The Cu(111)/WC(0001) interface models with eight configurations were investigated using DFT.•C-terminal interfaces are generally more favorable in terms of bonding strength.•The bridge site stack interface structure is unstable.•The interface energy of W-terminated interfaces is usually less than that of C-terminated interfaces.•W-terminated and C-terminated interfaces exhibit weak metallic bond and strong ionic bond features, respectively.
Directed cell migration is a physical process that requires dramatic changes in cell shape and adhesion to the extracellular matrix. For efficient movement, these processes must be spatiotemporally ...coordinated. To a large degree, the morphological changes and physical forces that occur during migration are generated by a dynamic filamentous actin (F-actin) cytoskeleton. Adhesion is regulated by dynamic assemblies of structural and signaling proteins that couple the F-actin cytoskeleton to the extracellular matrix. Here, we review current knowledge of the dynamic organization of the F-actin cytoskeleton in cell migration and the regulation of focal adhesion assembly and disassembly with an emphasis on how mechanical and biochemical signaling between these two systems regulate the coordination of physical processes in cell migration.
In this study, we investigate the catalytic performance of palladium (Pd) nanocatalysts with different surface atomic structures for activating electroless copper (Cu) deposition on liquid crystal ...polymer (LCP) substrates. These nanocatalysts include Pd nanocubes featuring {100} facets of square atomic arrangement as their predominant surface structure and Pd spherical nanoparticles characterized by random atomic arrangements, synthesized using an aqueous method. Our electrochemical measurements reveal that the induction time for the growth of Cu films is significantly shorter when utilizing Pd nanocubes compared to Pd nanospheres. This shorter induction time signifies a quicker initiation of Cu growth, primarily due to the presence of Pd {100} facets. Furthermore, we also develop a surface modification approach involving a crosslinking reaction that utilizes the highly branched polyethylenimine and linear polyvinylpyrrolidone on the Pd nanocubes. This method not only facilitates the adsorption of Pd nanocubes onto the LCP substrates but also achieves a robust peel adhesion strength (630 gf/cm) of the resulting Cu films, exceeding the industrial adhesion goal of 500 gf/cm. Moreover, in-depth synchrotron X-ray photoelectron spectroscopy analysis provides valuable insights into the depth-dependent chemical changes within the Cu films and proves the removal of Cu oxides after the acid treatment.
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Despite the remarkable advances in mitigating ice formation and accretion, however, no engineered anti-icing surfaces today can durably prevent frost formation, droplet freezing, and ice accretion in ...an economical and ecofriendly way. Herein, sustainable and low-cost electrolyte hydrogel (EH) surfaces are developed by infusing salted water into a hydrogel matrix for avoiding icing. The EH surfaces can both prevent ice/frost formation for an extremely long time and reduce ice adhesion strength to ultralow value (Pa-level) at a tunable temperature window down to −48.4 °C. Furthermore, ice can self-remove from the tilted EH surface within 10 s at −10 °C by self-gravity. As demonstrated by both molecular dynamic simulations and experiments, these extreme performances are attributed to the diffusion of ions to the interface between EH and ice. The sustainable anti-icing properties of EH can be maintained by replenishing in real-time with available ion sources, indicating the promising applications in offshore platforms and ships.
In this study, individual Al2O3 and Cr2O3 coatings and Cr2O3-25, 50, 75 wt% Al2O3 composite coatings were applied on carbon steel by atmospheric plasma spraying method. Corrosion experiments were ...performed on as-sprayed and epoxy resin sealed coatings including potentiodynamic polarization, electrochemical impedance spectroscopy and long-term immersion in 3.5 wt% NaCl solution. Phase composition and microstructure of the coatings were investigated by x-ray diffraction, optical microscopy and scanning electron microscopy, before and after the corrosion experiment. The results showed that the Cr2O3 coating exhibited the best corrosion resistance, due to the densest microstructure and highest adhesion strength. The Cr2O3-25 wt% Al2O3 coating had the highest interconnected porosities and thus had the least corrosion resistance compared to other coatings. In general, the as-sprayed coatings induced a maximum increase of 3.93 times the polarization resistance (Rp) in the polarization experiment and a 3.5 times increase in the charge transfer resistance (Rct) in the EIS experiment, which was not significant. Stresses caused by increased volume of corrosion products in the coating-substrate interface resulted in the spallation of Cr2O3-25, 50 wt% Al2O3 coatings from the substrate over long-term of immersion. The adhesion strength of the coatings was a determining criterion for the long-term durability of the coatings. The sealing treatment resulted in a significant increase in Rp and Rct.
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