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Although bulk superhydrophobic materials are considered as promising candidates because of their durable anti-wetting properties, they still face some challenges such as complicated fabrication processes and inherent brittleness. In the present study, we prepared a robust and flexible bulk superhydrophobic film by a facile “UV curing + solvent evaporation” method. Using this method, a cross-linked organic gel is generated by rapid thiol–ene photopolymerization (within 60 s) of a polydimethylsiloxane (PDMS)/hydrophobic silica/cyclohexane suspension and is further transformed into a superhydrophobic porous film after solvent evaporation. With the optimized solvent/polymer mass ratio (15 : 1), the superhydrophobic PDMS/silica film shows high stretchability (∼68%) and solid mechanical strength because of the appropriate cross-linking degree and low porosity of the polymer skeleton. The silica particles and porous structure cooperatively form self-similar and hierarchical structures across the film bulk, which can be repetitively exposed to the surface by abrasion to maintain durable superhydrophobicity. Consequently, the robustness and regenerative characteristics of the hierarchical structure enable the film to maintain durable superhydrophobicity while facing various mechanical damages such as 1000 cycles of stretching–releasing and 500 abrasion cycles. Taking advantage of the regenerative characteristics, the damaged superhydrophobic film surface is rapidly recovered by sanding treatment without the use of healing agents. [ABSTRACT FROM AUTHOR]

Although superhydrophobic porous membranes are considered to be very promising candidates for oil–water separation, their fabrication methods often involve complicated treatments to build a coating with micro/nano-features on a porous mesh (called “coating on a mesh structure”), which can lead to weak mechanical stability of the superhydrophobic surfaces and the formation of inhomogeneous membrane pores. Herein, we report a facile and environmentally friendly 3D printing approach to fabricate superhydrophobic membranes with an ordered porous structure for oil–water separation using hydrophobic nanosilica-filled polydimethylsiloxane (PDMS) ink. The addition of nanosilica can improve the mechanical strength of the ink and thus ensures the formation of desired topographical structures without the risk of collapsing during 3D printing. Through adjusting the geometrical parameters, a superhydrophobic PDMS membrane was obtained, which mainly depended on the roughness at the sub-millimeter scale. More importantly, the 3D printing approach described herein integrated the superhydrophobic surface into the porous framework and resulted in a mechanically durable superhydrophobic membrane, which successfully avoids the weak interface adhesion issue that arises from the traditional “coating on a mesh structure.” Moreover, the pore size of the printed membrane could be easily adjusted via a computer program to optimize both the liquid flux and separation efficiency of the membranes. The maximum oil–water separation efficiency (∼99.6%) could be achieved for the printed porous membrane with the pore size of 0.37 mm, which also exhibited a high flux of ∼23 700 L m−2 h−1. [ABSTRACT FROM AUTHOR]

SERS optrodes were used to “fish” aqueous drops from superhydrophobic surfaces. The technique led to an improvement of 2–3 orders of magnitude in the lowest detectable amount of the Raman probe nile blue A, reaching 25 fg (34 attomoles). Further tests run on samples containing pesticide revealed that 20 pg of triazophos could be clearly detected from a single drop. [ABSTRACT FROM AUTHOR]

A surface enhanced Raman scattering (SERS) substrate, capable of extracting small amounts of organic species from surfaces of different types of materials with variable roughness, has been fabricated. The substrate consists of Ag NPs encapsulated in poly(vinyl alcohol) (PVA) hydrogels, commonly known as PVA “slime”. Unlike traditional SERS substrates, such as colloidal suspensions, the resulting PVA slime SERS substrate presents good viscoelasticity, allowing it to conform to the surface of various materials of arbitrary roughness. Surfaces of different materials, including sandpapers, cotton, metal, and wood, previously contaminated with nile blue A (NBA) were analyzed with the PVA slime SERS substrate. Limits of detection (LOD) as low as 100 ppb (0.79 ng in a total amount on an area of ∼3 cm2) were achieved for all surfaces tested. Pesticides and Sudan red III on the glass surface have also been detected, with a LOD of 1.6 ng per ∼3 cm2. [ABSTRACT FROM AUTHOR]

Enhancing the electrolyte wetting of separators by surface modification is very critical to prepare highperformance lithium-ion batteries. Herein, we present a new approach named hyperthermal hydrogen induced cross-linking (HHIC) technology to increase the electrolyte-affinity of polypropylene (PP) separators by covalently cross-linking a thin layer of poly(ethylene oxide) (PEO) on surface-inert PP separators. With the HHIC treatment, the polar functionalities of PEO (e.g. -OH, C-O-C) can be preserved through selective cleavage of C-H bonds and subsequent cross-linking of resulting carbon radicals generated on PEO and PP chains. As proved by solvent rinsing tests, contact angle measurements and Fourier transform infrared spectroscopy, a PEO coating was found firmly fixed on the separator surface, which results in significantly improved wetting with the electrolyte. Electrochemical measurements on subsequent lithium-ion batteries with the modified separator by HHIC treatment exhibit a lower internal resistance but higher capacity retention when compared to the pristine separator. HHIC treatment is concluded to be a highly efficient and environmental-friendly approach for separator surface modification without need for other chemical additives (e.g. chemical cross-linkers, initiators, and catalysts) and can preserve the desired macroscopic material properties of separators such as pore structures and mechanical strength. [ABSTRACT FROM AUTHOR]

In this work, we report a new approach to resolve a practical problem in producing conductive polystyrene/reduced-graphene-oxide (PS/RGO) composites, i.e. the dilemma that raising the conductivity detrimentally compromises the environmental friendliness of the process because the prevalent chemistry designs emphasize raising conductivity in RGO production by employing strong and toxic chemicals or energy-consuming heat treatments. These designs then rely on organic solvents, chemical functionalization, and stabilizers to overcome the difficulty in dispersing and incorporating RGO into the polymer matrix. In our new design, we emphasize that a compact percolated three-dimensional microcellular RGO network with long-range order is the most effective use of RGO for high composite conductivity. With this guide, GO and non-polar PS mono-dispersed microspheres are co-dispersed in water, with GO stably adsorbing on the microspheres. PS/GO microspheres are then reduced with a nontoxic reducing agent such as vitamin C. PS/RGO microspheres are subsequently hot-pressed into a composite with the required compact percolated three-dimensional microcellular RGO structure. Experimental data collected from the resultant composites validate the design and indeed show low percolation threshold (0.08 vol%), high conductivity (20.5 S m−1), and good compliance with the principles of green chemistry. [ABSTRACT FROM AUTHOR]

Correction for ‘A robust and flexible bulk superhydrophobic material from silicone rubber/silica gel prepared by thiol–ene photopolymerization’ by Yongsheng Li et al., J. Mater. Chem. A, 2019, DOI: URL10.1039/c8ta11111a/URL. [ABSTRACT FROM AUTHOR]

Considering the harmfulness of nitrogen dioxide (NO 2 ), it is important to develop NO 2 sensors with high responses and low limits of detection. In this study, we synthesize a novel SnO-Sn 3 O 4 heterostructure through a one-step solvothermal method, which is used for the first time as an NO 2 sensor. The material exhibits three-dimensional flower-like microparticles assembled by two-dimensional nanosheets, in situ -formed SnO-Sn 3 O 4 heterostructures, and large specific surface area. Gas sensing measurements show that the responses of the SnO-Sn 3 O 4 heterostructure to 500 ppb NO 2 are as high as 657.4 and 63.4 while its limits of detection are as low as 2.5 and 10 parts per billion at 75 °C and ambient temperature, respectively. In addition, the SnO-Sn 3 O 4 heterostructure has an excellent selectivity to NO 2 , even if exposed to mixture gases containing interferential part with high concentration. The superior sensing properties can be attributed to the in situ formation of SnO-Sn 3 O 4 p-n heterojunctions and large specific surface area. Therefore, the SnO-Sn 3 O 4 heterostructure having excellent NO 2 sensing performances is very promising for applications as an NO 2 sensor or alarm operated at a low operating temperature., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)