Mrs Bulletin最新文献

Unlike animals, plants lack motion-generating systems such as a central nervous system or muscles, but they have successfully developed mechanisms to sense and respond to environmental changes, ensuring their survival. Most of their movements rely on the movement of water into and out of their cells or tissues, which are intrinsically soft and porous. Understanding and harnessing these natural processes can lead to the development of environmentally friendly and biocompatible soft actuator systems. This article explains the strategies employed by plants to generate movement through water transportation, categorizing them into osmosis-driven and hygroscopic swelling-driven mechanisms. Additionally, we discuss the latest trends in soft actuators that replicate plant water-utilizing movements, suggest directions for further development, and provide a review of practical applications.

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Electronically controllable actuators have shrunk to remarkably small dimensions, thanks to recent advances in materials science. Currently, multiple classes of actuators can operate at the micron scale, be patterned using lithographic techniques, and be driven by complementary metal oxide semiconductor (CMOS)-compatible voltages, enabling new technologies, including digitally controlled micro-cilia, cell-sized origami structures, and autonomous microrobots controlled by onboard semiconductor electronics. This field is poised to grow, as many of these actuator technologies are the firsts of their kind and much of the underlying design space remains unexplored. To help map the current state of the art and set goals for the future, here, we overview existing work and examine how key figures of merit for actuation at the microscale, including force output, response time, power consumption, efficiency, and durability are fundamentally intertwined. In doing so, we find performance limits and tradeoffs for different classes of microactuators based on the coupling mechanism between electrical energy, chemical energy, and mechanical work. These limits both point to future goals for actuator development and signal promising applications for these actuators in sophisticated electronically integrated microrobotic systems.

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Our ability to measure and image biology at small scales has been transformative for developing a new generation of insect-scale robots. Because of their presence in almost all environments known to humans, insects have inspired many small-scale flying, swimming, crawling, and jumping robots. This inspiration has affected all aspects of the robots’ design, ranging from gait specification, materials properties, and mechanism design to sensing, actuation, control, and collective behavior schemes. This article highlights how insects have inspired a new class of small and ultrafast robots and mechanisms. These new robots can circumvent motors’ force-velocity tradeoffs and achieve high-acceleration jumping, launching, and striking through latch-mediated spring-actuated (LaMSA) movement strategies. In the article, we apply a solution-driven bioinspired design framework to highlight the process for developing LaMSA-inspired robots and systems, starting with understanding the key biological themes, abstracting them to solution-neutral principles, and implementing such principles into engineered systems. Throughout the article, we emphasize the roles of modeling, fabrication, materials, and integration in developing bioinspired LaMSA systems and identify critical future enablers such as integrative design approaches.

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The fabrication of heterostructures and superlattices, which governs charge transport in materials, traditionally relies on high-temperature epitaxial processes. However, van der Waals (vdW) integration, a bond-free approach, has emerged as a versatile and gentle alternative. It allows for the integration of dissimilar materials beyond the thermodynamic limits, preserving material integrity and optimizing device performance. This approach has been instrumental in creating high-performance contacts for delicate lead halide perovskites, enabling quantum transport studies at low temperatures. Additionally, vdW integration has led to the development of vdW superlattices, and the chiral molecular intercalation superlattice offers a platform for exploring exotic chiral-induced spin selectivity effect and unconventional superconductivity. Together, vdW integration offers precise control over material composition and electronic structure, paving the way for innovative devices and the exploration of emergent quantum phenomena, all at the atomic scale. This groundbreaking strategy holds immense potential for advancing fundamental physical investigations and technological possibilities.

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To power miniature mobile robots, the body structure must integrate actuators, sensing, wiring, an energy source, power converters, and computing. The system-level performance relies on the interplay among these complementary elements and the fabrication technologies that enable them. While new materials, fabrication, and bioinspired designs are enabling advancements toward insect-scale untethered and autonomous robots, challenges remain in achieving high power efficiency fast actuation and heterogeneous integration. This article overviews the state of the art, opportunities, and challenges covered in this issue of MRS Bulletin.

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Quantum information processing and quantum sensing is a central topic for researchers who are part of the Materials Research Society and the Quantum Staging Group is providing leadership and guidance in this context. We convened a workshop before the 2022 MRS Spring Meeting and covered four topics to explore challenges that need to be addressed to further promote and accelerate the development of materials with applications in quantum technologies. This article captures the discussions at this workshop and refers to the pertinent literature.

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Bioresorbable medical electronics represents an emerging class of implantable sensors and/or stimulators that can be absorbed harmlessly in the human body, eliminating the patients’ permanent loads and the needs for risky secondary removal surgeries. This article specifically highlights recent advances in organic encapsulans that govern the lifetime, mechanical and electrical stability of the bioresorbable electronic implants. The core content focuses on the physics and chemistry of bioresorbable polymers, spanning degradation mechanism, mechanical stretchablilty, water permeability, and interfacial adhesiveness, along with tissue adhesion. Following discussions highlight the use cases of these polymers as organic encapsulations in bioresorbable electronic implants with therapeutic purposes, including nerve regeneration, pain block, and temporary cardiac pacing. A concluding section summarizes research opportunities of organic materials for advanced bioresorbable electronic systems.

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Liquid phase (or liquid cell) transmission electron microscopy (TEM) has become a powerful platform for in situ investigation of various chemical processes at the nanometer or atomic level. The electron beam for imaging can also induce perturbation to the chemical processes. Thus, it has been a concern that the observed phenomena in a liquid cell could deviate from the real-world processes. Strategies have been developed to overcome the electron-beam-induced issues. This article provides an overview of the electron-beam effects, and discusses various strategies in liquid cell TEM study of nucleation, growth, and self-assembly of nanoscale materials, where an electron beam is often used to initiate the reactions, and highly electron-beam-sensitive electrochemical reactions.

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