Formation of dual-responsive polystyrene/polyaniline microspheres with sea urchin-like and core-shell morphologies

Hollow Nitrogen-Doped porous carbon spheres decorated with atomically dispersed Ni-N3 sites for efficient electrocatalytic CO2 reduction

Hollow nitrogen-doped porous carbon spheres (HNCS) with plentiful coordination N sites, high surface area, and superior electrical conductivity are ideal catalyst supports due to their easily access of reactants to active sites and excellent stability. To date, nevertheless, little has been reported on HNCS as supports to metal-single-atomic sites for CO₂ reduction (CO₂R). Here we report our findings in preparation of nickel-single-atom catalysts anchored on HNCS (Ni SAC@HNCS) for highly efficient CO₂R. The obtained Ni SAC@HNCS catalyst exhibits excellent activity and selectivity for the electrocatalytic CO₂-to-CO conversion, achieving a Faradaic efficiency (FE) of 95.2% and a partial current density of 20.2 mA cm^-2. When applied to a flow cell, the Ni SAC@HNCS delivers above 95% FE_CO over a wide potential range and a peak FE_CO of 99%. Further, there is no obvious degradation in FE_CO and the current for CO production during continuous electrocatalysis of 9 h, suggesting good stability of Ni SAC@HNCS.

Research on preparation and properties of pH responsive superhydrophobic coating modified by SEBS

Smart materials with reversible wettability have attracted a lot of attention for application in sewage treatment. In this work, a pH-responsive polymer was prepared via the one-step free radical polymerization of 3-(trimethoxysilyl) acrylate and 2-dimethylaminoethyl methacrylate. The obtained pH-responsive polymer was then coated with a hydrogenated styrene–ethylene–butadiene–styrene block copolymer to endow the material with pH-responsive switchable superhydrophilic and superhydrophobic properties. Due to the excellent self-cleaning and mechanical stability of the coating, it was used to modify paper, which was then successfully utilized in the treatment of oily wastewater, showing great potential for use in advanced applications.

Insect-inspired nanofibrous polyaniline multi-scale films for hybrid polarimetric imaging with scattered light

We demonstrate a bio-inspired coating for novel imaging and sensing designs: the coating sorts different colors and linear polarizations. This coating, composed of conducting, nanofibrous polyaniline in an inverse opal film (PANI-IOF), is inexpensive and can feasibly be deposited over large areas on a range of flexible and non-flat substrates. With PANI IOFs, light is scattered into azimuthally polarized Debye rings. Subsequently, the diffracted speckle patterns carry compressed representations of the polarized illumination, which we reconstruct using shallow neural networks.

Smart surfaces with reversibly switchable wettability: Concepts, synthesis and applications

As a growing hot research topic, manufacturing smart switchable surfaces has attracted much attention in the past a few years. The state-of-the-art study on reversibly switchable wettability of smart surfaces has been presented in this systematic review. External stimuli are brought about to render the alteration in chemical conformation and surface morphology to drive the wettability switch. Here, starting from the fundamental theories related to the surfaces wetting principles, highlights on different triggers for switchable wettability, such as pH, light, ions, temperature, electric field, gas, mechanical force, and multi-stimuli are discussed. Different applications that have various wettability requirement are targeted, including oil-water separation, droplets manipulation, patterning, liquid transport, and so on. This review aims to provide a deep insight into responsive interfacial science and offer guidance for smart surface engineering. It ends with a summary of current challenges, future opportunities, and potential solutions on smart switch of wettability on superwetting surfaces.

Surface Nanostructuration and Wettability of Electrodeposited Poly(3,4-ethylenedioxypyrrole) and Poly(3,4-propylenedioxypyrrole) Films Substituted by Aromatic Groups

In the aim to obtain parahydrophobic materials (both high contact angles and high hysteresis) for possible applications in water harvesting systems, we report the synthesis of novel 3,4-ethylenedioxypyrrole (EDOP) and 3,4-propylenedioxypyrrole (ProDOP) monomers with aromatic rings on the 3,4-alkylenedioxy bridge and the resulting conducting polymer films were prepared by electropolymerization. We show that the surface properties can be tuned by the nature of the aromatic ring (phenyl, biphenyl, diphenyl, naphthalene, fluorene, and pyrene) and the polymerizable core (EDOP or ProDOP). The best results are obtained with both EDOP and diphenyl, with which extremely high hydrophobic properties (up to 116°) are obtained, even if the polymers are intrinsically hydrophilic. These surfaces could be applied in the future, for example, in water harvesting systems or in water/oil separation membranes. The synthesis strategy is extremely interesting, and many other molecules will be envisaged in the future.

Seeded swelling polymerized sea urchin-like core–shell typed polystyrene/polyaniline particles and their electric stimuli-response

Sea urchin-like polystyrene/polyaniline particles were synthesized by a seeded swelling polymerization. When dispersed in silicone oil to produce an electrorheological (ER) fluid, they exhibit typical ER behaviors with better dispersion stability.

Surfactant-free switchable emulsions using CO2-responsive particles

Surfactant-free emulsions are prepared using bi-wetting particles which occupy the oil-water interface to effectively reduce the oil-water interfacial area. The equilibrium position of the particle at the interface is determined by its wettability. CO2-reponsive chemical functional groups are grafted onto the surface of silica particles. Particles with only CO2-switchable functional groups are capable of stabilizing oil-in-water emulsions. Particles prepared with both CO2-responsive and hydrophobic chemical functional groups on its surface are capable of stabilizing water-in-oil emulsions. Emulsion stability is disturbed when the wettability of the stabilizing particle is altered by introducing CO2 gas to the biphasic mixture, leading to phase separation of emulsions prepared using the functionalized particles. The emulsion stability can be re-established by the removal of CO2 through air sparging. The presence of CO2 imposes positive surface charge to the responsive particles, increasing wettability and, consequently, the ability of the particles to destabilize emulsions.