SI Video S1. TiO 2-Au Micromotors Motion Remotely Triggered by UV Light and a Control. SI Video S2. TiO 2-Au Micromotors Moving Towards to TiO 2 Side in Water. SI Video S3. Motion of TiO 2-Au Micromotors in Different NaCl Concentration Environment under UV Light. SI Video S4. Motion of TiO 2-Au Micromotors with Different Coating Layer under UV Light. SI Video S5. Motion of Light-Driven Micromotors under Different UV Light Intensities in Water. SI Video S6. UV Light Triggered "Stop and Go" of a Micromotor. SI Video S7. Directional Control of TiO 2-Ni-Au Micromotors. SI Video S8. Motion of Light-Driven Micromotors in Different Conditions.

This focus article addresses fundamental and practical aspects of investigating polymers with lower critical solution temperature behavior.

In modern society, traffic and transportation and the manufacturing industry and construction industries continuously release large amounts of dust and particles into the atmosphere, which can cause heavy air pollution, leading to health hazards. The haze disaster, a serious problem in developing countries such as China and India, has become one of the main issues of global environmental pollution in recent decades. Many air filtration technologies have been developed. Air filtration using electrospun fibers that intercept fine particles/volatile organic gases/bacterium is a relatively new, but highly promising, technique. Due to their interconnected nanoscale pore structures, highly specific surface areas, fine diameters, and porous structure as well as their ability to incorporate active chemistry on a nanoscale surface, electrospun fibers are becoming a promising versatile platform for air filtration. In this review, following a short introduction concerning the need for air filtration and filtration theory and mechanism, electrospun nanofibers membranes for air filtration have been highlighted, including the preparation (electrospinning process) and the parameters relevant to filtration efficacy. Additionally, various types (function) of the electrospun air filtration membranes have been classified in detail. Furthermore, their potential in the filtration of fine particles and chemical pollutants has been discussed. Finally, the challenges of their practical application and the future prospects have been summarized. Given that some advanced electrospun air filtration nanofibrous membranes exist for treating different contaminants from various types of polluted atmosphere, it is believed that they should make a significant contribution in protection against air pollution.

This article highlights the properties of stimuli-responsive bio-based polymeric systems and their main intelligent applications.

Interventions and policies for tackling air pollution issues exist and have been proven to be effective. Membrane materials of nanofibrous morphology are attractive for air filtration, and further alleviate the environmental issues. Electrospinning as a simple and versatile way to fabricate ultrafine fibers has been attracting tremendous attention. Herein, the recent researches and future trends of green electrospinning are expounded from the aspects of green degradable materials, green solution electrospinning, and solvent‐free electrospinning. The green degradable materials, including biomass materials, biosynthetic polymer materials, and chemical synthetic materials are reviewed. Following the concept of green electrospinning, electrospun polymer nanofibers via aqueous solution are discussed; additionally, further trends of solvent‐free electrospinning including melt‐electrospinning, anion‐curing electrospinning, UV‐curing electrospinning, thermo‐curing electrospinning, and supercritical CO2‐assisted electrospinning are highlighted. Furthermore, the applications of these electrospun nanofibrous membranes in the field of air filtration are discussed. In the end, the challenges of green electrospinning and future prospects are summarized. The development of green electrospinning is reviewed with an emphasis on current advanced solvent‐free research, where electrospun nanofibrous membranes are contributing to promising treatment strategies to solve environment issue.

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A novel light-driven Au-WO@C Janus micromotor based on colloidal carbon WO nanoparticle composite spheres (WO@C) prepared by one-step hydrothermal treatment is described. The Janus micromotors can move in aqueous media at a speed of 16 μm/s under 40 mW/cm UV light due to diffusiophoretic effects. The propulsion of such Au-WO@C Janus micromotors (diameter ∼ 1.0 μm) can be generated by UV light in pure water without any external chemical fuels and readily modulated by light intensity. After depositing a paramagnetic Ni layer between the Au layer and WO, the motion direction of the micromotor can be precisely controlled by an external magnetic field. Such magnetic micromotors not only facilitate recycling of motors but also promise more possibility of practical applications in the future. Moreover, the Au-WO@C Janus micromotors show high sensitivity toward extremely low concentrations of sodium-2,6-dichloroindophenol (DCIP) and Rhodamine B (RhB). The moving speed of motors can be significantly accelerated to 26 and 29 μm/s in 5 × 10 wt % DCIP and 5 × 10 wt % RhB aqueous solutions, respectively, due to the enhanced diffusiophoretic effect, which results from the rapid photocatalytic degradation of DCIP and RhB by WO. This photocatalytic acceleration of the Au-WO@C Janus micromotors confirms the self-diffusiophoretic mechanism and opens an opportunity to tune the motility of the motors. This work also offers the light-driven micromotors a considerable potential for detection and rapid photodegradation of dye pollutants in water.

We demonstrate a facile and environmentally friendly approach to prepare well-dispersed graphene sheets by g-ray induced reduction of a graphene oxide (GO) suspension in N,N-dimethyl formamide (DMF) at room temperature. GO is reduced by the electrons generated from the radiolysis of DMF under g-ray irradiation. The reduced GO by g-ray irradiation (G-RGO) can be re-dispersed in many organic solvents, and the resulting suspensions are stable for two weeks due to the stabilization of N(CH 3 ) 2 + groups on G-RGO. Additionally, G-RGO is efficient in improving the conductivity of polystyrene (PS). Its PS nanocomposites exhibit a sharp transition from electrically insulating to conducting with a low percolation threshold of 0.24 vol% and a high electrical conductivity of 45 S m À1 is obtained with only 2.3 vol% of G-RGO. The superior electrical conductivity is attributed to the uniform dispersion of the G-RGO sheets in the PS matrix.