Cellulose can be dissolved in precooled (-12 °C) 7 wt % NaOH-12 wt % urea aqueous solution within 2 min. This interesting process, to our knowledge, represents the most rapid dissolution of native cellulose. The results from 13 C NMR, 15 N NMR, 1 H NMR, FT-IR, small-angle neutron scattering (SANS), transmission electron microscopy (TEM), and wide-angle X-ray diffraction (WAXD) suggested that NaOH "hydrates" could be more easily attracted to cellulose chains through the formation of new hydrogen-bonded networks at low temperatures, while the urea hydrates could not be associated directly with cellulose. However, the urea hydrates could possibly be self-assembled at the surface of the NaOH hydrogen-bonded cellulose to form an inclusion complex (IC), leading to the dissolution of cellulose. Scattering experiments, including dynamic and static light scattering, indicated that most cellulose molecules, with limited amounts of aggregation, could exist as extended rigid chains in dilute solution. Further, the cellulose solution was relatively unstable and could be very sensitive to temperature, polymer concentration, and storage time, leading to additional aggregations. TEM images and WAXD provided experimental evidence on the formation of a wormlike cellulose IC being surrounded with urea. Therefore, we propose that the cellulose dissolution at -12 °C could arise as a result of a fast dynamic self-assembly process among solvent small molecules (NaOH, urea, and water) and the cellulose macromolecules.

The separation of oil–water mixtures in highly acidic, alkaline, and salty environment remains a great challenge. Simple, low‐cost, efficient, eco‐friendly, and easily scale‐up processes for the fabrication of novel materials to effective oil–water separation in highly acidic, alkaline, and salty environment, are urgently desired. Here, a facile approach is reported for the fabrication of stable hydrogel‐coated filter paper which not only can separate oil–water mixture in highly acidic, alkaline, and salty environment, but also separate surfactant‐stabilized emulsion. The hydrogel‐coated filter paper is fabricated by smartly crosslinking filter paper with hydrophilic polyvinyl alcohol through a simple aldol condensation reaction with glutaraldehyde as a crosslinker. The resultant multiple crosslinked networks enable the hydrogel‐coated filter paper to tolerate high acid, alkali, and salt up to 8 m H2SO4, 10 m NaOH, and saturated NaCl. It is shown that the hydrogel‐coated filter paper can separate oil–water mixtures in highly acidic, alkaline, and salty environment and oil‐in‐water emulsion environment, with high separation efficiency (>99%).

Summary: A superhydrophobic coating was facilely fabricated in one step by casting bisphenol A polycarbonate (PC) solution under moisture. Vapor‐induced phase separation occurred during the solidifying process and a rough surface with a micro‐nano‐binary structure (MNBS) similar to the microstructure shown on lotus leaf was formed.SEM image of a single micro‐flower.magnified imageSEM image of a single micro‐flower.

Anti-biofouling surfaces are of high importance owing to their crucial roles in biosensors, biomedical devices, food processing, the marine industry, etc. However, traditional anti-biofouling surfaces based on either the release of biocidal compounds or surface chemical/physical design cannot satisfy the practical demands when meeting real-world complex conditions. The outstanding performances of natural anti-biofouling surfaces motivate the development of new bioinspired anti-biofouling surfaces. Herein, a novel strategy is proposed for rationally designing bioinspired anti-biofouling surfaces based on superwettability. By utilizing the trapped air cushions or liquid layers, Lotus leaf inspired superhydrophobic surfaces, fish scales inspired underwater superoleophobic surfaces, and Nepenthes pitcher plants inspired omniphobic slippery surfaces have been successfully designed as anti-biofouling surfaces to effectively resist proteins, bacteria, cells, and marine organisms. It is believed that these novel superwettability-based anti-biofouling surfaces will bring a new era to both biomedical technology and the marine industry, and will greatly benefit human health and daily life in the near future.

Seaweed (Saccharina japonica) is found to have excellent superoleophobicity in salt solutions, which results from its high content of polysaccharides. Inspired by this, coatings with salt‐tolerant underwater superoleophobicity and ultralow oil adhesion are successfully fabricated using calcium alginate. During immersion in artificial seawater for 30 days, the coatings effectively repel various types of oil, including crude oil and viscous silicon oil, demonstrating their great potential as a marine oil‐repellent coating.

Superhydrophobic surfaces are widely found in nature, inspiring the development of excellent antiwater surfaces with barrier coatings isolating the underlying materials from the external environment. Here, the naturally occurring superhydrophobicity of lotus seedpod surfaces is reported. Protective coatings that mimic the lotus seedpod are fabricated on AZ91D Mg alloy surfaces with the synergistic effect of robust superhydrophobicity and durable corrosion resistance. The predesigned titanium dioxide films are coated on AZ91D by an in situ hydrothermal synthesis technique. Through sonication assisted electroless plating combined with a self‐assembling method, the densely packed Cu‐thiolate layers are uniformly plated with robust adhesion on the Mg alloy substrate, which function as a superhydrophobic barrier that can hold back the transport of water and corrosive ions contained such as Cl−. Notably, the two extreme wetting behaviors (superhydrophilicity and superhydrophobicity) as well as corrosion resistance and improved corrosion resistance can be easily controlled by removal of the hydrophobic materials (n‐dodecanethiol) at elevated temperature (350 °C) and modifying them at room temperature for 18 cycles, indicative of exceptional adhesion between the superhydrophobic coating and the underlying AZ91D Mg alloy.

A super‐hydrophobic surface (see Figure), possessing a microscale and nanoscale hierarchical structure similar to the surface structure of the lotus leaf, was prepared in one step from a micellar solution of polypropylene‐block‐poly(methyl methacrylate).

Segmented polyether-polyurethane (PU)/montmorillonite nanocomposites have been synthesized with poly(tetramethylene glycol), 4,4-diphenylmethane diisocyanate, propylenediamine, and montmorillonite. The nanoscale silicate layers are intercalated or exfoliated in the PU matrix, which are characterized by X-ray diffraction pattern and transmission electron microscopy. The PU/montmorillonite composites have been investigated by FT-IR dichroism during the stretching process in order to study the hard and soft chain orientation, hydrogen bonding, and strain induced by crystallization of the soft segment chains in PU. DSC experiment indicates that the soft phase Tg increases with the montmorillonite content. The mechanical analysis showed that tensile strength,Young's modulus, and elongation at break increase markedly, 1700% elongation at break for the composite containing 2.0 wt % montmorillonite.