The increasing number of oil spill accidents have a catastrophic impact on our aquatic environment. Recently, special wettable materials used for the oil/water separation have received significant research attention. Due to their opposing affinities towards water and oil, i.e., hydrophobic and oleophilic, or hydrophilic and oleophobic, such materials can be used to remove only one phase from the oil/water mixture, and simultaneously repel the other phase, thus achieving selective oil/water separation. Moreover, the synergistic effect between the surface chemistry and surface architecture can further promote the superwetting behavior, resulting in the improved separation efficiency. Here, recently developed materials with special wettability for selective oil/water separation are summarized and discussed. These materials can be categorized based on their oil/water separating mechanisms, i.e., filtration and absorption. In each section, representative studies will be highlighted, with emphasis on the materials wetting properties and innovative aspects. Finally, challenges and future research directions in this emerging and promising research field will be briefly described.

Recent Development of Advanced Materials with Special Wettability for Selective Oil/Water Separation.

Bioinspired polydopamine (PDA) has served as a universal coating to nanoparticles (NPs) for various biomedical applications. However, one remaining critical question is whether the PDA shell on NPs is stable in vivo. In this study, we modified gold nanoparticles (GNPs) with finely controlled PDA nanolayers to form uniform core/shell nanostructures (GNP@PDA). In vitro study showed that the PDA-coated GNPs had low cytotoxicity and could smoothly translocate to cancer cells. Transmission electron microscopy (TEM) analysis demonstrated that the PDA nanoshells were intact within cells after 24 h incubation. Notably, we found the GNP@PDA could partially escape from the endosomes/lysosomes to cytosol and locate close to the nucleus. Furthermore, we observed that the PDA-coated NPs have very different uptake behavior in two important organs of the liver and spleen: GNP@PDA in the liver were mainly uptaken by the Kupffer cells, while the GNP@PDA in the spleen were uptaken by a variety of cells. Importantly, we pro...

Mussel-Inspired Polydopamine: A Biocompatible and Ultrastable Coating for Nanoparticles in Vivo

Inspired by the superhydrophobic lotus surface in nature, special wettability has attracted a lot of interest and attention in both academia and industry In this review, theoretical models and fabrication strategies of superhydrophobic textiles have been discussed in detail The strategies for constructing fabric surfaces with an anti-wetting property are categorized and discussed based on the morphology of particles coated on the textile fibre Such special wettability textile surfaces are demonstrated with self-cleaning, oil/water separation, self-healing, UV-blocking, photocatalytic, anti-bacterial, and flame-retardant performances Correspondingly, potential applications have been illustrated for self-cleaning, oil/water separation, asymmetric/anisotropic wetting janus fabric, microfluidic manipulation, and micro-templates for patterning In each section, representative studies are highlighted with emphasis on the special wetting ability and other relevant properties Finally, the difficulties and challenges for practical application were briefly discussed

/pdf/a-review-on-special-wettability-textiles-theoretical-models-3tl6y6tjp1.pdf

A review on special wettability textiles: theoretical models, fabrication technologies and multifunctional applications

Superhydrophobic cotton fabrics were prepared via a facile and environmentally friendly strategy to deposit an organically modified silica aerogel (ormosil) thin film onto the fabrics first, followed by polydimethylsiloxane (PDMS) topcoating. The PDMS–ormosil coating displayed a uniform 3D fractal-like structure with numerous loose micro-scale pores, while the PDMS layer increased the binding strength of the hierarchical ormosil film to form a highly robust porous network on the fibers. In comparison with hydrophilic cotton fabrics, the modified cotton fabric exhibited a highly superhydrophobic activity with a water contact angle higher than 160° and a sliding angle lower than 10°. The as-constructed PDMS–ormosil@fabrics are able to withstand 100 cycles of abrasion and 5 cycles of accelerated machine wash without an apparent decrease of superhydrophobicity. In addition, the superhydrophobic cotton fabrics are very stable in strongly acidic and alkaline solutions. Furthermore, the superhydrophobic coating has no or negligible adverse effect on the important textile physical properties of the cotton fabric, such as the strength, air permeability, and flexibility. The composite super-antiwetting fabrics have demonstrated excellent anti-fouling, self-cleaning ability and are highly efficient in oil–water separation for various oil–water mixtures. This facile synthesis technique has the advantages of scalable fabrication of multifunctional fabrics for potential applications in self-cleaning and versatile water–oil separation.

Robust fluorine-free superhydrophobic PDMS–ormosil@fabrics for highly effective self-cleaning and efficient oil–water separation

Hydrogen production from water splitting by photo/photoelectron-catalytic process is a promising route to solve both fossil fuel depletion and environmental pollution at the same time. Titanium dioxide (TiO2) nanotubes have attracted much interest due to their large specific surface area and highly ordered structure, which has led to promising potential applications in photocatalytic degradation, photoreduction of CO2, water splitting, supercapacitors, dye-sensitized solar cells, lithium-ion batteries and biomedical devices. Nanotubes can be fabricated via facile hydrothermal method, solvothermal method, template technique and electrochemical anodic oxidation. In this report, we provide a comprehensive review on recent progress of the synthesis and modification of TiO2 nanotubes to be used for photo/photoelectro-catalytic water splitting. The future development of TiO2 nanotubes is also discussed.

One‐dimensional TiO2 Nanotube Photocatalysts for Solar Water Splitting

Inspired by the surface geometry and composition of the lotus leaf with its self-cleaning behavior, in this work, a TiO2@fabric composite was prepared via a facile strategy for preparing marigold flower-like hierarchical TiO2 particles through a one-pot hydrothermal reaction on a cotton fabric surface. In addition, a robust superhydrophobic TiO2@fabric was further constructed by fluoroalkylsilane modification as a versatile platform for UV shielding, self-cleaning and oil–water separation. The results showed TiO2 particles were uniformly distributed on the fibre surface with a high coating density. In comparison with hydrophobic cotton fabric, the TiO2@fabric exhibited a high superhydrophobic activity with a contact angle of ∼160° and a sliding angle lower than 10°. The robust superhydrophobic fabric had high stability against repeated abrasion without an apparent reduction in contact angle. The as-prepared composite TiO2@fabric demonstrated good anti-UV ability. Moreover, the composite fabric demonstrated highly efficient oil–water separation due to its extreme wettability contrast (superhydrophobicity/superoleophilicity). We expect that this facile process can be readily and widely adopted for the design of multifunctional fabrics for excellent anti-UV, effective self-cleaning, efficient oil–water separation, and microfluidic management applications.

Robust superhydrophobic TiO2@fabrics for UV shielding, self-cleaning and oil–water separation

Nanomaterials have offered an opportunity for molecular imprinting to extract templates easily and achieve large binding capacity. In this paper, silicon nanowires were employed as the reinforcement material in protein molecular imprinting with dopamine as the monomer and bovine hemoglobin as the template molecule. In the experiments, the imprinted nanowires showed fast adsorption kinetics (took up 75% of the equilibrium amount during only 5 min), significant selectivity and large binding capacity (213.7 mg g−1) for the template protein. Furthermore, the stability and regeneration were also investigated, which indicated that the imprinted nanowires had outstanding reusability.

Molecularly imprinted polymer-coated silicon nanowires for protein specific recognition and fast separation

Magnetism-assisted assembled porous Fe3O4 nanoparticles and their electrochemistry for dopamine sensing

Control over the crystal phase, crystallinity, morphology of AgVO3 via protein inducing process.

A simple and cost-effective strategy was developed to synthesize Ag dendrites via an aqueous chemical route based on spontaneous galvanic displacement between silver (I) ions and copper foil under hydrothermal condition. Ag dendrites with [100], [110], and [111] growth direction can be prepared by adjusting the content of polyvinyl pyrrolidone. The Ag dendrites exhibited fine and well reproducible surface-enhanced Raman scattering effect using Rhodamine 6G as model molecule. There is a corresponding relation between the false color plot of Raman intensity and the dendrite morphology. Among the products, the Ag dendrites growing along [100] direction have the best surface enhancement ability, and a possible explanation was proposed. The results might open up new thinking on surface-enhanced Raman scattering by proper crystal growth and design. Copyright © 2011 John Wiley & Sons, Ltd. Supporting information may be found in the online version of this article.

Tao Chen

Papers

Robust superhydrophobic TiO2@fabrics for UV shielding, self-cleaning and oil–water separation

Molecularly imprinted polymer-coated silicon nanowires for protein specific recognition and fast separation

Magnetism-assisted assembled porous Fe3O4 nanoparticles and their electrochemistry for dopamine sensing

Control over the crystal phase, crystallinity, morphology of AgVO3 via protein inducing process.

Surface-enhanced Raman scattering on silver dendrite with different growth directions