Untethered Microactuators

In article number 2100158, Marc del Pozo, Larisa Florea, Albert P. H. J. Schenning, and co-workers present a new liquid crystalline photoresist for the creation of untethered microactuators using direct laser writing by two-photon polymerization. The presented responsive microstructures have a high crosslink density that facilitates the creation of complex 3D geometries which exhibit temperature induced anisotropic shape changes. Such untethered microactuators are attractive to fields including microfluidics or medicine.

Tailoring Oxygen Vacancy

Fabricating oxygen vacancy on surface of metal oxides is performed as an effective strategy to improve the humidity sensitivity of materials even under low humidity level. This provides more possibilities for the application of low-cost humidity sensors in some emerging fields in terms of intelligent skin, human-machine interface, contactless screen, etc. More details can be found in article number 2100166 by Yingming Xu, Lihua Huo, and co-workers.

Herein, recent progress in printed flexible and stretchable strain sensors for on-skin electronics is reviewed. This review starts with an overview of strain sensing mechanisms, followed by a summary of various printing methods for fabricating strain sensors. Finally, the applications for on-skin electronics are presented, focusing on healthcare, sports performance monitoring, and human–machine interfaces.

This review focuses on palladium (Pd)-based electrocatalysts for the oxygen reduction reaction (ORR) in alkaline media. After a brief introduction and fundamental ORR mechanism overview, various strategies for delicately designing high-performance Pd-based catalysts are throughout discussed, together with associated examples. Perspectives with challenges and new insights are further outlined, and some emerging research directions are also proposed.

Herein, the progress of multidimensional tungsten oxides (WO₃)-based photoactive materials are introduced. To bypass the intrinsic limitations caused by spatial dimensionality and to enhance the optoelectronic properties for solar energy conversion, mixed-dimensional WO₃ materials are consequently summarized. The preliminary results in this fast-growing field are anticipated to guide the development of diverse mixed-dimensional photoactive materials.

Untethered microactuators hold enormous potential for applications in fields spanning medicine to microfluidics. Their miniaturization still remains a challenge, specially when specific geometries displaying preprogrammed deformations are desired. Here, a liquid crystalline photoresist with a high fraction of crosslinkers is reported and the structural and optical responses of several temperature responsive 3D constructs are studied.

Fabricating oxygen vacancy on surface of metal oxides is performed as an effective strategy to improve the humidity sensitivity of materials even under low humidity level. This provides more possibilities for the application of low-cost humidity sensors in some emerging fields in terms of intelligent skin, human–machine interface, contactless screen, etc.

An in situ grown carbon nanofiber on a Ti substrate is free of binders and current collectors. Stemming from its 3D and interconnected texture, it features a high specific surface area and an excellent conductivity. Its integration as a capacitor electrode with redox electrolytes produces supercapacitors with big and stable capacitances as well as high power and energy densities.

Fluorescent organic crystal (E)-1-(4-(iodo)phenyl)iminomethyl-2-hydroxyl-naphthalene (IPIN) exhibits exceptional mechanical flexibility and selective self-absorption of the blue part of its emission. IPIN crystal forms a triply-bent waveguide during micromechanical fabrication. Integration of a triply-bent waveguide with a singly-bent waveguide creates a unique organic photonic integrated circuit (OPIC) geometry. This innovative OPIC carries excitation position-dependent and direction-specific long-pass-filtered narrowband optical signals with different split ratios.

A photothermal-activatable liposome carrying tissue plasminogen activator (tPA) is designed to provide photoacoustic image-guided and photothermal-controlled release of tPA for ischemic stroke treatment.

A novel Sn-bonded Si anode coated with PVDF-derived carbon is proposed. During hot pressing, Cu₃Si as well as Cu₃Sn is in situ formed at the interface of the active materials and the Cu current collector. In addition, Sn melts and serves as the metallic binder during hot pressing, which also results in a strong metallurgical bonding between electrode materials.