The ORCID identification number(s) for the author(s) of this article can be found under https://doi.org/10.1002/adma.202109547. Fluid-bicontinuous gels are unique materials that allow two distinct fluids to interact through a percolating, rigid scaffold. Current restrictions for their use are the large fluid-channel sizes (>5 µm), limiting the fluid-fluid interaction surface-area, and the inability to flow liquids through the channels. In this work a scalable synthesis route of nanoparticle stabilized fluid-bicontinuous gels with channels sizes below 500 nm and specific surface areas of 2 m 2 cm −3 is introduced. Moreover, it is demonstrated that liquids can be pumped through the fluid-bicontinuous gels via electroosmosis. The fast liquid flow in the fluid-bicontinuous gel facilitates their use for molecular separations in continuous-flow liquid-liquid extraction. Together with the high surface areas, liquid flow through fluid-bicontinuous gels enhances their potential as highly permeable porous materials with possible uses as microreaction media, fuel-cell components, and separation membranes.

Rope making is a millennia old technique to collectively assemble numerous weak filaments into flexible and high tensile strength bundles. However, delicate soft matter fibers lack the robustness to be twisted into bundles by means of mechanical rope making tools. Here, weak microfibers with tensile strengths of a few kilopascals are combined into ropes via microfluidic twisting. This is demonstrated for recently introduced fibers made of bicontinuous interfacially jammed emulsion gels (bijels). Bijels show promising applications in use as membranes, microreactors, energy and healthcare materials, but their low tensile strength make reinforcement strategies imperative. Hydrodynamic twisting allows to produce continuous bijel fiber bundles of controllable architecture. Modelling the fluid flow field reveals the bundle geometry dependence on a subtle force balance composed of rotational and translational shear stresses. Moreover, combining multiple bijel fibers of different compositions enables the introduction of polymeric support fibers to raise the tensile strength to tens of megapascals, while simultaneously preserving the liquid like properties of the bijel fibers for transport applications. Hydrodynamic twisting shows potentials to enable the combination of a wide range of materials resulting in composites with features greater than the sum of their parts.

helical microfibers are chiral, highly stretchable, and can be employed as micro-motors [7] and -swimmers. [8] However, current microfiber fabrication approaches offer limited control of the helical geometry.Microfluidic spinning technology (MST) has emerged as a tool to precisely tune the spatiotemporal chemical composition within microfibers. [9,10] MST employs a liquid precursor solution, which transforms into a semisolid fiber after flowing out of a microscopic orifice. Typical solidification mechanisms include ionic or chemical cross-linking, [11] photopolymerization, [12] and phase separation. [13] Helical fibers are formed in MST via the liquid rope coiling effect. [14,15] This hydrodynamic instability results in helices with large pitch lengths. [2] However, it remains difficult to combine multiple fibers into double, triple, or higher-order helices via liquid rope coiling. A better control of the helical multiplicity and shape can be realized upon actively rotating the microfibers. This has been shown for instance by Yasuda et al. in a planetary centrifuge. [16] But, these and other prevailing active fiber twisting methods are based on batch processing, limiting their technological potentials. [17,18] Recently, we have introduced microfluidic twisting (MT) to continuously generate composite helical fiber assemblies. [19] microfluidic twisting enables the combination of multiple helical fibers into high-order helices. The constituent fibers can have different sizes, twisting degrees, or chemical compositions. Although our prior work has explained the effect of the hydrodynamic forces controlling the helical pitch, the fundamental driving force of the helical assembly has not been elaborated. This knowledge gap has restricted the controlled collection of uniform helical fibers. Moreover, it has limited the choices of fiber precursor dispersions, resulting in strong, but inflexible helical fibers. [19] Here, we close this knowledge gap and show how centrifugal forces during microfluidic twisting enable the continuous assembly and collection of flexible, stimuli-responsive microropes. The assembly and collection of the microropes depends on the direction of the centrifugal force, which is determined by the density difference between the individual rope filaments and the surrounding fluid. The rope filaments in our work are composed of bicontinuous interfacially jammed emulsions gels (bijels) [20,21] formed via solvent transfer induced phase separation (STrIPS). [22][23][24][25] Bijels have potential applications as catalytic emulsions, [26] separation membranes, [23] battery components, [27,28] and sensors. [29] Interestingly, the density of the In microfluidics, centrifugal forces are important for centrifugal microfluidic chips and curved microchannels. Here, an unrecognized use of the centrifugal effect in microfluidics is introduced. The assembly of helical soft matter fibers in a rotating microcapillary is investigated. During assembly, the fibers undergo phase separation, generating particle stabilized...

Segregation of atomic species in metastable solid-solution alloys results in a gradual change of the alloy’s properties, sometimes rendering the materials ineffective for the particular task they were designed for. An example of such a case is the sensitization of strong and lightweight Mg-rich aluminum alloys used in marine applications. The ASTM standard is an acid-corrosion test (G67), a destructive and lengthy procedure that requires large specimens analyzed off-site. Ultrasound is a well-known tool for nondestructive material characterization and it can offer a solution for on-site testing. To this end, the sensitivity of ultrasonic parameters to the degree of material degradation through sensitization has been identified. Velocity and attenuation for shear and longitudinal waves were measured as a function of sensitization for 5083 and 5456 aluminum alloys with two different methods: Resonant Ultrasound Spectroscopy (RUS) and Pulse Echo (PE). The longitudinal and shear velocities change by 0.5% and 1.5%, respectively, while the attenuation coefficient of longitudinal waves changes by of 20% (all represent saturation values). The JMAK equation for phase kinetics is used to understand the observed evolution of the acoustic parameters vs. sensitization.