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All-day passive radiative cooling has recently attracted tremendous interest by reflecting sunlight and radiating heat to the ultracold outer space. While some progress has been made, it still remains big challenge in fabricating highly efficient and low-cost radiative coolers for all-day and all-climates. Herein, we report a hierarchically structured polymethyl methacrylate (PMMA) film with a micropore array combined with random nanopores for highly efficient day- and nighttime passive radiative cooling. This hierarchically porous array PMMA film exhibits sufficiently high solar reflectance (0.95) and superior longwave infrared thermal emittance (0.98) and realizes subambient cooling of ~8.2 °C during the night and ~6.0 °C to ~8.9 °C during midday with an average cooling power of ~85 W/m2 under solar intensity of ~900 W/m2, and promisingly ~5.5 °C even under solar intensity of ~930 W/m2 and relative humidity of ~64% in hot and moist climate. The micropores and nanopores in the polymer film play crucial roles in enhancing the solar reflectance and thermal emittance.

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Artificial special wetting surfaces have drawn much interest due to their important applications in many fields. Nevertheless, tremendous challenges still remain for the fabrication of wetting surfaces with durable and self-healing properties. Here, recent progress of durable, self-healing wetting surfaces is highlighted by discussing the fabrications of several typical wetting surfaces including superhydrophobic surfaces, superamphiphobic surfaces, underwater superoleophobic surfaces, and high hydrophilic antifouling surfaces based on expertise and related research experience. To conclude, some perspectives on the future research and development of these special wetting surfaces are presented.

Transparent superamphiphobic surfaces that repel various liquids have many important applications, but there are critical challenges in their fabrication, such as expensive or complicated fabrication methods, contradictions between the rough surface for superamphiphobicity and smooth surface for transparency, large-area fabrication, etc. Herein, we report a simple and effective strategy for large-scale fabrication of robust, transparent, and superomniphobic polymer films by combined unidirectional rubbing and heating-assisted assembly technology. The obtained polymer films display two kinds of special structures of monolayer ordered re-entrant geometries with either hexagonally triangular protrusions or with hexagonally rectangular micropillars, depending upon the sphere diameters of silica templates, and demonstrate excellent repellence to water and low-surface-tension liquids, as well as high transparency.

Epitaxial growth of Co on GaAs͑001͒ and its in-plane magnetic anisotropy are studied using reflection high-energy electron diffraction, a high-resolution transmission electron microscope, and the magneto-optical Kerr effect. In the initial and final stages of growth, Co exists in single-crystalline body-centered-cubic ͑bcc͒ and hexagonal-closed-packed ͑hcp͒ phases, respectively, while in the middle stage the coexistence of the bcc and hcp structures is observed. For the bcc Co thin films on GaAs͑001͒, a fourfold in-plane magnetic anisotropy with easy axes along the ͗100͘ directions is realized and discussed. ͓S0163-1829͑98͒04915-7͔The 3d transition metals exist in a variety of crystallographic and magnetic phases. Thin-film growth of these materials on crystalline substrates allows the forces present at the interface to drive the film into specific crystalline structures. These structures may be in a thermodynamically stable phase, a known high-pressure or high-temperature phase, or even a phase not previously observed. They greatly increase the variety of magnetic materials by essentially making ''new'' materials from ''old'' elements. 1The epitaxial growth of Co films serves as a good example. It is known that the hexagonal-close-packed ͑hcp͒ and face-centered-cubic ͑fcc͒ structures are, respectively, stable and metastable phases of Co. The body-centered-cubic ͑bcc͒ structure, which does not occur in nature, was realized by Prinz with epitaxial growth on a GaAs͑110͒ substrate. However, it was later pointed out by Liu and Singh that bcc Co is not a true metastable phase but a force-induced phase. 3The in-plane magnetic anisotropy of such a bcc Co thin film on GaAs͑110͒ was further determined and a negative value for the cubic anisotropy constant K 1 was proposed.2 If this were true, a fourfold in-plane magnetic anisotropy with easy axes along the ͗110͘ direction would then be expected in the bcc Co films on GaAs͑001͒ substrates. In fact, a fourfold in-plane magnetic anisotropy with the easy axes along the ͗100͘ rather than the ͗110͘ direction was observed by Blundell et al. 4 Interestingly, it was later argued by Gu et al. that Co films grown on GaAs͑001͒ were actually not bodycentered cubic but two-domain hexagonal close packed by which the fourfold magnetic anisotropy along the ͗100͘ direction could be explained by such a microstructure.5 Obviously, the epitaxial structure of Co on GaAs͑001͒ and its magnetic anisotropy are still very controversial. In this work, we present a clear picture of the epitaxial growth of Co on GaAs͑001͒, which clears up the previous controversy about the structure of Co thin films on GaAs͑001͒. With the help of this clear picture, we prove that the bcc Co films on GaAs͑001͒ show a fourfold in-plane magnetic anisotropy.Co films were grown in a molecular-beam epitaxy ͑MBE͒ growth chamber connected with the VG-ESCALAB-5 electron spectrometer system. The Te-doped GaAs͑001͒ singlecrystal wafers were polished and treated by ordinary device cleaning process. The final substrate cleaning w...

Hydro- and oleophobic (namely, omniphobic) coatings or surfaces have many important applications, but tremendous challenges in fabrication aspects still remain. Herein, we report a bioinspired design and nanofabrication of three-dimensional (3D) tribrachia-post arrays with re-entrant geometry (3D TPARG) for superhydrophobic and oleophobic polymer films or surfaces. By simply controlling the temperatures and time to treat silica colloidal templates, we can readily fabricate 3D ordered polymer arrays of tribrachia-posts or hexagonal tribrachia-posts with re-entrant geometries that resemble the skin of a springtail insect after the template is removed. These polymer surfaces exhibit excellent and self-healing superhydrophobicity and oleophobicity even against temperature, acids, alkalis, and mechanical damage. Moreover, their liquid-infused nanostructured surfaces still display very good liquid-sliding ability for water and oils. Our 3D TPARG design strategy may help the development of omniphobic polymer coatings or surfaces for practical applications in self-cleaning surfaces, liquid transport, antifouling materials, and many other important fields.