During the past decades major efforts in the field of porous materials have been directed toward control of the size, shape and uniformity of the pores. Carbide-derived carbons (CDCs) represent a new class of nanoporous carbons with porosity that can be tuned with sub-Ångström accuracy in the range 0.5-2 nm. CDCs have a more narrow pore size distribution than single-wall carbon nanotubes or activated carbons; their pore size distribution is comparable with that of zeolites. CDCs are produced at temperatures from 200-1200 o C as a powder, a coating, a membrane or parts with near-final shapes, with or without mesopores. They can find applications in molecular sieves, gas storage, catalysts, adsorbents, battery electrodes, supercapacitors, water/ air filters and medical devices. Although many carbides can be used to produce CDCs, this study was conducted on Ti 3 SiC 2 powders and bulk samples. Ti 3 SiC 2 is a soft ceramic with a lamellar structure (Supplement 1) that is commercially available and can easily be machined to any shape Four different techniques were independently used to measure the pore size: Ar, N 2 and methyl chloride, CH 3 Cl, sorption, as well as small-angle X-ray scattering (SAXS), as described in Methods. As can be seen in Fig. 1, pore sizes of CDCs increase with increasing temperature, from 0.51 nm at 300ºC, to 0.64 nm at 700ºC and 1.10 nm at 1100ºC. The sorption isotherms of low-temperature CDCs (up to 600°C) obtained using Isotherms of CDCs produced above 700°C were of type IV, which indicates the presence of mesopores. Total pore volumes observed for the samples produced at 700°, 900°, and 1100°C were almost the same, but the pore size distributions were different:Mesopore volume and size increased with increasing chlorination temperatures. Their equivalent radius was less than 3 nm at 700ºC (Fig. 1a) and about 6 nm at 1100ºC (Fig. 1b). Weight loss and energy-dispersive X-ray spectroscopy analysis of the samples after gives a very narrow peak in m(R g ) which accounts for most of the nanopore volume (Fig. 2b).SAXS confirms the aforementioned sorption data and shows that pore size can be controlled with better than 0.05 nm accuracy (Fig. 2c) -a remarkable result that has never been demonstrated for any other porous material.The interpretation of R g (Fig. 2c) With increasing temperature, the specific distance for jump of carbon atoms increases and the pore size increases accordingly. More equiaxial pores form in the 6 1000-1200ºC temperature range (Fig. 2c), which is consistent with XRD data (supplement 3) that show complete loss of interlayer correlations such that the pores no longer retain any memory of the precursor lattice.Microstructural studies of CDCs were conducted to explain their structural reorganization and the development of their porous structure with temperature. Raman spectroscopy (Fig. 3a,b) shows that carbon already forms at 200ºC. However, XRD (Fig. 3e). Noticeable ordering of graphite starts at 700ºC (Fig. 3d) and nanocrystalline graphite appears at 1200ºC (...

A “PDMS-in-water” emulsion approach is developed to construct a mechanochemically robust superhydrophobic cotton fabric with intelligent self-healing nature against intensive mechanical damage.

Flexible actuation of droplets is crucial for biomedical and industrial applications. Hence, various approaches using optical, electrical, and magnetic forces have been exploited to actuate droplets. For broad applicability, an ideal approach should be programmable and be able to actuate droplets of arbitrary size and composition. Here we present an “additive-free” magnetic actuation method to programmably manipulate droplets of water, organic, and biological fluids of arbitrary composition, as well as solid samples, on a ferrofluid-infused porous surface. We specifically exploit the spontaneously formed ferrofluid wetting ridges to actuate droplets using spatially varying magnetic fields. We demonstrate programmed processing and analysis of biological samples in individual drops as well as the collective actuation of large ensembles of micrometer-sized droplets. Such model respiratory droplets can be accumulated for improved quantitative and sensitive bioanalysis - an otherwise prohibitively difficult task that may be useful in tracking coronavirus.

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