Flexible and Stretchable Elastomer Composites Based on Lightweight Liquid Metal Foam Spheres with Pod-like Contacts

Holocellulose nanofibrils biomimetic entrapment of liquid metal enable ultrastrong, tough, and lower-voltage-driven paper device

Integrating liquid metal (LM) with wood fibers for flexible paper electronics is intriguing yet extremely challenging due to poor mechanical performance. Here, we disclose a hemicellulose trapping strategy to achieve exceptional ultrastrong and tough LM-based paper electronics. Holocellulose nanofibrils (HCNFs) with hemicellulose retention of approximately 20 % are found to effectively entrap nanoscale LM within the fibril network, analogous to spider silk capturing small water droplets. Phase separation of LM and coalescence of nanofibrils can be avoided during the fabrication process of sheet-like paper. The homogeneous distribution of nanoscale LM eliminates impairment and contributes to the dramatic enhancement of mechanical performance (tensile strength: 240 MPa; toughness: 16.5 MJ m-3). Further incorporating a small number of carbon nanotubes generates low-voltage-driven Joule heating performance with excellent heat generation capacity (200 °C at 4.0 V), surpassing LM-based elastomers, films, and textiles. Our study illuminates the remarkable potential of LM-based paper electronics and enables advanced flexible device applications.

Materials and Structural Designs toward Motion Artifact-Free Bioelectronics

Bioelectronics encompassing electronic components and circuits for accessing human information play a vital role in real-time and continuous monitoring of biophysiological signals of electrophysiology, mechanical physiology, and electrochemical physiology. However, mechanical noise, particularly motion artifacts, poses a significant challenge in accurately detecting and analyzing target signals. While software-based "postprocessing" methods and signal filtering techniques have been widely employed, challenges such as signal distortion, major requirement of accurate models for classification, power consumption, and data delay inevitably persist. This review presents an overview of noise reduction strategies in bioelectronics, focusing on reducing motion artifacts and improving the signal-to-noise ratio through hardware-based approaches such as "preprocessing". One of the main stress-avoiding strategies is reducing elastic mechanical energies applied to bioelectronics to prevent stress-induced motion artifacts. Various approaches including strain-compliance, strain-resistance, and stress-damping techniques using unique materials and structures have been explored. Future research should optimize materials and structure designs, establish stable processes and measurement methods, and develop techniques for selectively separating and processing overlapping noises. Ultimately, these advancements will contribute to the development of more reliable and effective bioelectronics for healthcare monitoring and diagnostics.

Flexible Grid Graphene Electrothermal Films for Real-Time Monitoring Applications

Flexible electrothermal films are crucial for protecting equipment and systems in cold weather, such as ice blockages in natural gas pipelines and icing on aircraft wings. Therefore, a flexible electric heater is one of the essential devices in industrial operations. One of the main challenges is to develop flexible electrothermal films with low operating voltage, high steady-state temperature, and good mechanical stability. In this study, a flexible electrothermal film based on graphene-patterned structures was manufactured by combining the laser induction method and the transfer printing process. The grid structure design provides accurate real-time monitoring for the application of electrothermal films and shows potential in solving problems related to deicing and clearing ice blockages in pipelines. The flexible electrothermal film can reach a high heating temperature of 165 °C at 15 V and exhibits sufficient heating stability. By employing a simple and efficient method to create a flexible, high-performance electrothermal film, we provide a reliable solution for deicing and monitoring applications.

Magnetically Induced Grid Structure for Enhancing the Performance of a Dual-Mode Flexible Sensor with Tactile/Touchless Perception

As an advanced sensing technology, dual-mode flexible sensing, integrating both tactile and touchless perception, propels numerous intelligent devices toward a more practical and efficient direction. The ability to incorporate multiple sensing modes and accurately distinguish them in real time has become crucial for technological advancements. Here, we proposed a dual-mode sensing system (B-MIGS) consisting of a dual-layer sensing device with a magnetically induced grid structure and a testing device. The system was capable of utilizing mechanical pressure to perceive tactile stimulation and magnetic sensing to simultaneously transduce touchless stimulation simultaneously. By leveraging the triboelectric effect, the decoupling of tactile and touchless signals in the presence of unknown signal sources was achieved. Additionally, the sensing characteristics of the B-MIGS were optimized by varying the curing magnetic induction intensity and magnetic particle concentration. The influence of the temperature and humidity on the sensing signals was also discussed. Finally, the practical value of the B-MIGS as a dual-mode monitoring system was demonstrated on soft petals and sensor arrays, along with exploration of its potential application in underwater environments.