In the field of bioinspired soft robotics, to accomplish sophisticated tasks in human fingers, electroactive artificial muscles are under development. However, most existing actuators show a lack of high bending displacement and irregular response characteristics under low input voltages. Here, based on metal free covalent triazine frameworks (CTFs), we report an electro-ionic soft actuator that shows high bending deformation under ultralow input voltages that can be implemented as a soft robotic touch finger on fragile displays. The as-synthesized CTFs, derived from a polymer of intrinsic microporosity (PIM-1), were combined with poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT-PSS) to make a flexible electrode for a high-performance electro-ionic soft actuator. The proposed soft touch finger showed high peak-to-peak displacement of 17.0 mm under ultralow square voltage of ±0.5 V, with 0.1 Hz frequency and 4 times reduced phase delay in harmonic response compared with that of a pure PEDOT-PSS-based actuator. The significant actuation performance is mainly due to the unique physical and chemical configurations of CTFs electrode with highly porous and electrically conjugated networks. On a fragile display, the developed soft robotic touch finger array was successfully used to perform soft touching, similar to that of a real human finger; device was used to accomplish a precise task, playing electronic piano.

Electro-active ionic soft actuators have been intensively investigated as an artificial muscle for soft robotics due to their large bending deformations at low voltages, small electric power consumption, superior energy density, high safety and biomimetic self-sensing actuation. However, their slow responses, poor durability and low bandwidth, mainly resulting from improper distribution of ionic conducting phase in polyelectrolyte membranes, hinder practical applications to real fields. We report a procedure to synthesize efficient polyelectrolyte membranes that have continuous conducting network suitable for electro-ionic artificial muscles. This functionally antagonistic solvent procedure makes amphiphilic Nafion molecules to assemble into micelles with ionic surfaces enclosing non-conducting cores. Especially, the ionic surfaces of these micelles combine together during casting process and form a continuous ionic conducting phase needed for high ionic conductivity, which boosts the performance of electro-ionic soft actuators by 10-time faster response and 36-time higher bending displacement. Furthermore, the developed muscle shows exceptional durability over 40 days under continuous actuation and broad bandwidth below 10 Hz, and is successfully applied to demonstrate an inchworm-mimetic soft robot and a kinetic tensegrity system.

This manuscript deals with the increased and selective nitrate reduction under visible light over a WN co-doped titania photocatalyst. A series of WN co-doped titania nanomaterials were synthesized with varying tungsten content and were characterized by TEM, XRD, UV-vis and nitrogen adsorption–desorption studies. Tungsten doped materials are found to be noodle shaped and mesoporous with a stable anatase phase after 500 °C calcination. Peak shifting in the XRD pattern indicates the tungsten doping in the crystal lattice. Visible light absorption increases with the increasing tungsten amount. Among the studied hole scavengers, formic acid was found to be the best for nitrate reduction with more than 94% nitrogen gas selectivity. The amount of hole scavenger also controls the reaction efficiency and product selectivity. Both nitrate reduction and nitrogen gas selectivity increases with WN co-doping in comparison to only N doped titania. High nitrate reduction with formic acid is attributed to the formation of CO₂˙⁻ species having high reduction potential. The material with 2% tungsten shows the highest surface area and the best photocatalytic activity under visible light. Presence of anion like chloride increases the nitrate photoreduction. Overall high nitrate reduction can be attributed to the synergistic effect of tungsten and nitrogen co-doping, optimum surface hydroxyl group, mesoporosity and appreciable visible light absorption of the materials.

Pyrazole‐linked covalent organic polymer is synthesized using an asynchronous double Schiff base from readily available monomers. The one‐pot reaction features no metals as a building block or reagent, hence facilitating the structural purity and industrial scalability of the design. Through a single‐crystal study on a model compound, the double Schiff base formation is found to follow syn addition, a kinetically favored product, suggesting that reactivity of the amine and carbonyls dictate the order and geometry of the framework building. The highly porous pyrazole polymer COP‐214 is chemically resistant in reactive conditions for over two weeks and thermally stable up to 425 °C in air. COP‐214 shows well‐pronounced gas capture and selectivities, and a high CO₂/N₂ selectivity of 102. The strongly coordinating pyrazole sites show rapid uptake and quantitative selectivity of Pd (II) over several coordinating metals (especially Pt (II)) at all pH points that are tested, a remarkably rare feature that is best explained by detailed analysis as the size‐selective strong coordination of Pd onto pyrazoles. Density functional theory (DFT) calculations show energetically favorable Pd binding between the metal and N‐sites of COP‐214. The polymer is reusable multiple times without loss of activity, providing great incentives for an industrial prospect.