Liquid Metal-Based Self-Healing Conductors for Flexible and Stretchable Electronics.

Flexible and stretchable electronics rely on compliant conductors as essential building materials. However, these materials are susceptible to wear and tear, leading to degradation over time. In response to this concern, self-healing conductors have been developed to prolong the lifespan of functional devices. These conductors can autonomously restore their properties following damage. Conventional self-healing conductors typically comprise solid conductive fillers and healing agents dispersed within polymer matrices. However, the solid additives increase the stiffness and reduce the stretchability of the resulting composites. There is growing interest in utilizing gallium-based liquid metal alloys due to their exceptional electrical conductivity and liquid-phase deformability. These liquid metals are considered attractive candidates for developing compliant conductors capable of automatic recovery. This perspective delves into the rapidly advancing field of liquid metal-based self-healing conductors, exploring their design, fabrication, and critical applications. Furthermore, this article also addresses the current challenges and future directions in this active area of research.

Achieving Exceptional Thermal and Hydrolytic Resistance in Chemically Circular Polyesters via In-Chain 1,3-Cyclobutane Rings.

Polyesters, a highly promising class of circular polymers for achieving a closed-loop sustainable plastic economy, inherently exhibit material stability defects, especially in thermal and hydrolytic instability. Here, we introduce a class of polyesters, P(4R-BL) (R=Ph, Bu), featuring conformationally rigid 1,3-cyclobutane rings in the backbone. These polyesters not only exhibit superior thermostability (Td,5%=376-380 °C) but also demonstrate exceptional hydrolytic resistance with good integrity even after 1 year in basic and acidic aqueous solutions, distinguishing themselves from typical counterparts. Tailoring the flexibility of the side group R enables the controlled thermal and mechanical performance of P(4Ph-BL) and P(4Bu-BL) to rival durable syndiotactic polystyrene (SPS) and low-density polyethylene (LDPE), respectively. Significantly, despite their high stability, both polyesters can be effectively depolymerized into pristine monomers, establishing a circular life cycle.

YOLOv8-ACU: improved YOLOv8-pose for facial acupoint detection.

Introduction: Acupoint localization is integral to Traditional Chinese Medicine (TCM) acupuncture diagnosis and treatment. Employing intelligent detection models for recognizing facial acupoints can substantially enhance localization accuracy. Methods: This study introduces an advancement in the YOLOv8-pose keypoint detection algorithm, tailored for facial acupoints, and named YOLOv8-ACU. This model enhances acupoint feature extraction by integrating ECA attention, replaces the original neck module with a lighter Slim-neck module, and improves the loss function for GIoU. Results: The YOLOv8-ACU model achieves impressive accuracy, with an mAP@0.5 of 97.5% and an mAP@0.5-0.95 of 76.9% on our self-constructed datasets. It also marks a reduction in model parameters by 0.44M, model size by 0.82 MB, and GFLOPs by 9.3%. Discussion: With its enhanced recognition accuracy and efficiency, along with good generalization ability, YOLOv8-ACU provides significant reference value for facial acupoint localization and detection. This is particularly beneficial for Chinese medicine practitioners engaged in facial acupoint research and intelligent detection.

Ultrastretchable Electrically Self-Healing Conductors Based on Silver Nanowire/Liquid Metal Microcapsule Nanocomposites.

Stretchable conductive nanocomposites are essential for deformable electronic devices. These conductors currently face significant limitations, such as insufficient deformability, significant resistance changes upon stretching, and drifted properties during cyclic deformations. To tackle these challenges, we present an electrically self-healing and ultrastretchable conductor in the form of bilayer silver nanowire/liquid metal microcapsule nanocomposites. These nanocomposites utilize silver nanowires to establish their initial excellent conductivity. When the silver nanowire networks crack during stretching, the microcapsules are ruptured to release the encased liquid metal for recovering the electrical properties. This self-healing capability allows the nanocomposite to achieve ultrahigh stretchability for both uniaxial and biaxial strains, minor changes in resistance during stretching, and stable resistance after repetitive deformations. The conductors have been used to create skin-attachable electronic patches and stretchable light-emitting diode arrays with enhanced robustness. These developments provide a bioinspired strategy to enhance the performance and durability of conductive nanocomposites.

Perimeter procedure to produce average equivalent area grain size.

A new method of perimeter procedure to produce average equivalent area grain size on orientation imaging microscopy (OIM) micrograph was developed. When the OIM micrograph was exported with the practical size of pixel equal to the electron backscattering diffraction (EBSD) step size, the expression for perimeter procedure in producing the average equivalent area radius is r¯p=(2AmPm+wb2Es)±wb2Es (Pm and Am are the perimeter and area of grains, respectively, which can be measured using commercial image pro plus software; wb is the pixel width of the grain boundary which is suggested to set as 1 and Es is the EBSD step size). Experiments were conducted and the four methods intercept procedure, planimetric procedure, perimeter procfedure and statistical method were adopted to measure the average grain sizes for different conditions (polygonal grains and compressed polygonal grains, different EBSD step sizes, different grain boundary widths). The results showed that the average grain size by perimeter procedure remained relatively unchanged and close to the true average grain size for all conditions. It was demonstrated that perimeter procedure has an advantage in that it can produce reliable average grain size even when the pixel step size relative to the grain size is relatively large.

Sub-60 mV per decade switching in ion-gel-gated In-Sn-O transistors with a nano-thick charge trapping layer.

In this paper, we present a new method for reducing the subthreshold swing (SS) of ionic-modulated oxide field-effect transistors (FETs) below 60 mV per decade. The electrical performances of ion gel-gated In-Sn-O FETs with and without a nano-thick Al2O3 charge trapping layer are compared and studied. A significant SS reduction in the In-Sn-O FETs is observed when naturally oxidized Al2O3 and an ion gel are used as the gate stacking dielectric layer. The back sweep SS reaches as low as ∼27 mV per decade and extends over three orders of magnitude in drain current. A theoretical explanation for these results based on energy band diagrams is presented. The proposed devices described here have the potential to open up new avenues for further development of low power electronics, as well as for energy efficient memristive devices and synaptic electronics.