Tough Al-alginate/poly(N-isopropylacrylamide) (PNIPAM) hydrogel has been synthesized by introducing an interpenetrating network with hybrid physically cross-linked alginate and chemically cross-linked PNIPAM. Varying the concentration of AlCl3 regulates the mechanical properties of the tough hydrogel and tunes its lower critical solution temperature (LCST) as well. The tough Al-alginate/PNIPAM exhibits 6.3 ± 0.3 MPa of compressive stress and 9.95 of uniaxial stretch. Tunability of LCST is also achieved in a wide range within 22.5-32 °C. A bending beam actuator and a four-arm gripper made of bilayer (Na-alginate/PNIPAM)/(Al-alginate/PNIPAM) hydrogel as prototype of all-hydrogel soft robotics are demonstrated. A finite element (FE) simulation model is developed to simulate the deformation of the soft robotics. The FE simulation not only reproduces the deformation process of performed experiments but also predicts more complicated devices that can be explored in the future. This work broadens the application of temperature-responsive PNIPAM-based hydrogels.
During the past decade, solution-processed bulk-heterojunction (BHJ) organic solar cells (OSCs) have made great strides and power conversion efficiencies (PCEs) over 16% have been achieved. [1-6] However, the PCEs of top-performing
Octopuses can employ their tapered arms to catch prey of all shapes and sizes due to their dexterity, flexibility, and gripping power. Intrigued by variability in arm taper angle between different octopus species, we explored the utility of designing soft actuators exhibiting a distinctive conical geometry, compared with more traditional cylindrical forms. We find that these octopus-inspired conical-shaped actuators exhibit a wide range of bending curvatures that can be tuned by simply altering their taper angle and they also demonstrate greater flexibility compared with their cylindrical counterparts. The taper angle and bending curvature are inversely related, whereas taper angle and applied bending force are directly related. To further expand the functionality of our soft actuators, we incorporated vacuum-actuated suckers into the actuators for the production of a fully integrated octopus arm-inspired gripper. Notably, our results reveal that because of their enhanced flexibility, these tapered actuators with suckers have better gripping power than their cylindrical-shaped counterparts and require significantly larger forces to be detached from both flat and curved surfaces. Finally, we show that by choosing appropriate taper angles, our tapered actuators with suckers can grip, move, and place a remarkably wide range of objects with flat, nonplanar, smooth, or rough surfaces, as well as retrieve objects through narrow openings. The results from this study not only provide new design insights into the creation of next-generation soft actuators for gripping a wide range of morphologically diverse objects but also contribute to our understanding of the functional significance of arm taper angle variability across octopus species.
Graphdiyne (GDY), a rising star of 2D carbon allotropes with one‐atom‐thick planar layers, has achieved the coexistence of sp‐ and sp2‐hybridized carbon atoms in a 2D planar structure. In contrast to the prevailing carbon allotropes, GDY possesses Dirac cone structures, which endow it with unique chemical and physical properties, including an adjustable inherent bandgap, high‐speed charge carrier transfer efficiency, and excellent conductivity. Additionally, GDY also displays great potential in photocatalysis, rechargeable batteries, solar cells, detectors, and especially electrocatalysis. In this work, various GDY‐supported electrocatalysts are described and the reasons why GDY can act as a novel support are analyzed from the perspective of molecular structure, electronic properties, mechanical properties, and stability. The various electrochemical applications of GDY‐supported electrocatalysts in energy conversion such as hydrogen evolution reaction, oxygen evolution reaction, oxygen reduction reaction, overall water splitting, and nitrogen reduction reaction are reviewed. The challenges facing GDY and GDY‐based materials in future research are also outlined. This review aims at providing an in‐depth understanding of GDY and promoting the development and application of this novel carbon material.
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