Langmuir最新文献

In recent years, nanoporous graphene has shown greatpotentialin nanofluidic devices and ion separation applications. However, inmultilayer architectures, pore misalignment significantly suppressesion transport efficiency, and its underlying mechanism remains insufficientlyunderstood. To address this issue, this study employs molecular dynamicssimulations to systematically examine the effect of pore alignmentand electric field direction on ionic current rectification (ICR)in Janus bilayer nanoporous graphene (NPG). The results show that,with increasing pore offset, ions become strongly enriched in theNPG interlayer region, forming a localized high-concentration environmentthat hinders ion migration and induces an ICR inversion. Further analysisreveals that, under a fixed pore offset, tuning the angle betweenthe electric field and the membrane normal can effectively reconstructthe ionic distribution in the NPG, thereby enhancing transport asymmetrybetween forward and reverse directions. As a result, the rectificationinversion caused by pore misalignment can be recovered, yielding amaximum ICR ratio of approximately 30 in the fixed-functional-groupmodel. Notably, this enhancement in ICR is accompanied by a monotonicdecrease in electropumping efficiency, suggesting that ionic rectificationand directional water transport are not directly correlated. Thesefindings demonstrate that both pore offset and electric field orientationserve as key tunable parameters governing ICR performance in NPGs,providing a new strategy for the design of high-performance and controllableICR devices.

A toughinterconnected dual conductive network was constructedin cement mortar through the synergistic incorporation of one-dimensionalmultiwalled carbon nanotubes (MWCNTs), two-dimensional MXene nanosheets,and carboxylated cellulose nanofibers (CNFs). To minimize nanoparticleagglomeration and improve conductive-network continuity, a combinedstrategy integrating ultrasonic predispersion, in situ directionalassembly, and vacuum-assisted incorporation was adopted to regulatethe spatial organization of conductive nanocomponents within the cementitiousmatrix. The effects of different component dosages on electrical resistivity,stress sensitivity coefficient, mechanical properties, and microstructuralevolution were systematically investigated. The results showed thatthe incorporation of MXene significantly optimized the conductive-networktopology and reduced the percolation threshold of the ternary systemto 1.76 × 10^–4, corresponding to a 63.2% decreasecompared with the single-MWCNTs system. Among all groups, T30F30M25exhibited the best electromechanical synergy, with a 27.58% reductionin resistivity, a stress sensitivity coefficient of 0.081%/MPa, andincreases of 27.51% and 60.59% in compressive and flexural strengths,respectively, relative to the control group. Multiscale characterizationsdemonstrated that MXene promoted AFt and C–S–H gel formationand refined CH crystallites, while MWCNTs provided crack-bridgingpathways and CNFs improved conductive-network continuity through sterichindrance and interfacial regulation. Furthermore, electromechanicaldamage evolution analysis revealed that the bioinspired dual conductivenetwork effectively suppressed crack-induced conductive-path disruptionand enhanced conductive-network stability during crack propagation.Through the synergistic interaction among MXene, MWCNTs, and CNFs,a spatially continuous fiber–nanosheet interconnected architecturewas gradually established within the cement matrix, enabling the simultaneousenhancement of conductivity, self-sensing capability, mechanical performance,and electromechanical stability. This study provides a new biomimeticstrategy for the structural design and multiscale regulation of high-performanceself-sensing cement-based materials.

Mesoscale interfacial sliding responses bridge nanoscalesingle-asperitysliding mechanisms and macroscopically averaged frictional responses,enabling local pinning–depinning processes to be resolved withina finite contact region. Recent studies on strongly disordered roughinterfaces have revealed statistical features of mesoscale stick–slip,but how such interfacial sliding responses are affected by environmentaland mechanical conditions, and how they relate to interfacial morphology,remain unclear. Here, we investigate mesoscale stick–slip ata diamond–Cu interface using a custom-built probe sliding systemunder controlled environments and loading conditions. Air–vacuumcomparison revealed that ambient exposure amplified and destabilizedthe interfacial response, motivating subsequent vacuum-based measurements.Under vacuum, normal preload and sliding speed mainly changed theabsolute force response of stick–slip, while the recurrencelength and dominant spectral scale remained within a similar micrometer-scalerange. Further comparison with Cu surface topography showed that themain spectral band of the sliding response overlapped with weak topographicfeatures and fell within the autocorrelation-based surface correlationrange. These results indicate that mesoscale stick–slip recurrenceis associated with interfacial spatial heterogeneity, providing insightinto the link between interfacial morphology and sliding stabilityat diamond–metal contacts.