Membrane adsorbers with ultrahigh metal-organic framework loading for high flux separations.

Metal-organic frameworks (MOFs) with high porosity and designable functionality make it possible to access the merits of high permeability and selectivity. However, scalable fabrication methods to produce mixed matrix membranes (MMMs) with good flexibility and ultrahigh MOF loading are urgently needed yet largely unmet. Herein, we report a thermally induced phase separation-hot pressing (TIPS-HoP) strategy to roll-to-roll produce 10 distinct MOF-membranes (loadings up to 86 wt%). Ultrahigh-molecular-weight polyethylene interweaving the MOF particles contributes to their mechanical strength. Rejections (99%) of organic dyes with a water flux of 125.7 L m-2 h-1 bar-1 under cross-flow filtration mode. The micron-sized channels between the MOF particles translate into fast water permeation, while the porous MOFs reject solutes through rapid adsorption. This strategy paves ways for developing high-performance membrane adsorbers for crucial separation processes. As a proof-of-concept, the abilities of the membrane adsorbers for separating racemates and proteins have been demonstrated.

Carbon-Nanotube-Wrapped Spider Silks for Directed Cardiomyocyte Growth and Electrophysiological Detection.

The combination of nanostructures with biomaterials offers great opportunities in constructing innovative functional devices such as biosensors and actuators. Here, we create a multifunctional fiber by wrapping a thin film of carbon nanotubes (CNTs) on naturally found spider silks, which shows great flexibility and conductivity. The hybrid CNT-silk fiber demonstrates intimate contact with cardiomyocytes and can direct the cell growth and simultaneously record potential signals evoked from cell beating. Cell activities reflected in the form of potential signals have been monitored clearly and reliably through the CNT-silk fibers without degradation over the long term.

A facile route to isotropic conductive nanocomposites by direct polymer infiltration of carbon nanotube sponges.

Fabrication of high-performance nanocomposites requires that the nanoscale fillers be dispersed uniformly and form a continuous network throughout the matrix. Direct infiltration of porous CNT sponges consisting of a three-dimensional nanotube scaffold may provide a possible solution to this challenge. Here, we fabricated CNT sponge nanocomposites by directly infiltrating epoxy fluid into the CNT framework while maintaining the original network structure and CNT contact, with simultaneous improvement in mechanical and electrical properties. The resulting composites have an isotropic structure with electrical resistivities of 10 to 30 Ω·cm along arbitrary directions, much higher than traditional composites by mixing random CNTs with epoxy matrix. We observed reversible resistance change in the sponge composites under compression at modest strains, which can be explained by tunneling conduction model, suggesting potential applications in electromechanical sensors.

Large-area blown bubble films of aligned nanowires and carbon nanotubes.

Many of the applications proposed for nanowires and carbon nanotubes require these components to be organized over large areas with controlled orientation and density. Although progress has been made with directed assembly and Langmuir-Blodgett approaches, it is unclear whether these techniques can be scaled to large wafers and non-rigid substrates. Here, we describe a general and scalable approach for large-area, uniformly aligned and controlled-density nanowire and nanotube films, which involves expanding a bubble from a homogeneous suspension of these materials. The blown-bubble films were transferred to single-crystal wafers of at least 200 mm in diameter, flexible plastics sheets of dimensions of at least 225 x 300 mm(2) and highly curved surfaces, and were also suspended across open frames. In addition, electrical measurements show that large arrays of nanowire field-effect transistors can be efficiently fabricated on the wafer scale. Given the potential of blown film extrusion to produce continuous films with widths exceeding 1 m, we believe that our approach could allow the unique properties of nanowires and nanotubes to be exploited in applications requiring large areas and relatively modest device densities.