Vertical-Structure Overcomes the Strain Limit of Stretchable Organic Electrochemical Transistors.

Intrinsically stretchable organic electrochemical transistors (IS-OECTs), utilizing organic mixed ionic-electronic conductors (OMIECs) as their channel materials, have drawn great attention recently because of their potential to enable seamless integration between bioelectronic devices and living systems. However, the fabrication of IS-OECTs presents challenges due to the limited availability of OMIEC materials that possess the desired combination of mechanical and electrical properties. In this work, 1) we report the first successful fabrication of a vertical intrinsically stretchable OECT (VIS-OECT), achieved by using elastoadhesive electrodes; 2) we experimentally proved that vertical architecture can push the strain limit of an IS-OECT from 20% to 50%; and 3) the above finding introduces an unconventional design concept: the strain limit of an IS-OECT can surpass the intrinsic stretchability of the constituent OMIECs by employing vertical structure.

Coin-sized, fully integrated, and minimally invasive continuous glucose monitoring system based on organic electrochemical transistors.

Continuous glucose monitoring systems (CGMs) are critical toward closed-loop diabetes management. The field's progress urges next-generation CGMs with enhanced antinoise ability, reliability, and wearability. Here, we propose a coin-sized, fully integrated, and wearable CGM, achieved by holistically synergizing state-of-the-art interdisciplinary technologies of biosensors, minimally invasive tools, and hydrogels.

D-Mannitol/Graphene Phase-Change Composites with Structured Conformation and Thermal Pathways Allow Durable Solar-Thermal-Electric Conversion and Electricity Output.

Durable electricity generation from a phase-change material (PCM)-assisted solar thermoelectric generator (STEG) through photo-thermal-electric conversion is a promising way to take advantage of the clean solar energy. However, due to the deficient and mismatched thermal charging and discharging rates in the PCMs, the previous PCM-supported STEGs usually exhibit inefficient solar-thermal-electric conversion (<1%) and limited electricity output. In this work, we report a structured D-mannitol/graphene phase-change composite fabricated by a radial ice-template assembly and infiltration strategy, in which radially aligned graphene nanoplates are bridged by graphitized polyimide that offers multidirectional and interlaced thermal highways for rapid thermal charging, while the sample conformation is further regulated by the ice-template mold, promising the optimal charging and discharging balance in the PCM.

Tropocollagen-Inspired Hierarchical Spiral Structure of Organic Fibers in Epoxy Bulk for 3D High Thermal Conductivity.

Polymers are usually considered thermal insulators; however, significant enhancements in thermal conductivity (k) have been observed in oriented fibers and films. Despite being advantageous in real-world applications, extending the linear thermal-transport advantage of polymers into the 3D space in bulk materials is still limited due to the spatially interfacial phonon-conduction barriers. Herein, inspired by the structure of tropocollagen, it is discovered that weaving hierarchically arranged poly(p-phenylene benzobisoxazole) (PBO) fibers with a spiral configuration into an epoxy matrix can yield a 3D continuous thermal pathway.

Intrinsically Stretchable Organic Electrochemical Transistors with Rigid-Device-Benchmarkable Performance.

Intrinsically stretchable organic electrochemical transistors (OECTs) are being pursued as the next-generation tissue-like bioelectronic technologies to improve the interfacing with the soft human body. However, the performance of current intrinsically stretchable OECTs is far inferior to their rigid counterparts. In this work, for the first time, the authors report intrinsically stretchable OECTs with overall performance benchmarkable to conventional rigid devices.

A Universal Mechanochemistry Allows On-Demand Synthesis of Stable and Processable Liquid Metal Composites.

Gallium-based liquid metal (LM) is regarded as one of the most promising candidates for the new-generation jigsaw of stretchable electronics. Nonetheless, the obstacle for the LM application lies in its high surface tension and easy fluidity which leads to great difficulty in handling and processing. Herein, a cross-mechanochemistry between liquid metal and inorganic solid, mediated via the coordination binding between the empty electronic orbits of the former and the lone electron pair of the latter is reported.

Pushing OECTs toward Wearable: Development of a Miniaturized Analytical Control Unit for Wireless Device Characterization.

Organic electrochemical transistors (OECTs) have emerged as a next-generation biosensing technology because of their water-stability, cost-effectiveness, and ability to obtain high sensitivity at low operation voltage (mV). However, a miniaturized readout unit that can wirelessly characterize the overall performance of an OECT is still missing, which hinders the assembling of truly wearable OECT systems for continuous health-monitoring applications. In this work, we present a coin-sized analytical unit for remote and wireless OECT characterization, namely, a personalized electronic reader for electrochemical transistors (PERfECT).

Highly thermoconductive yet ultraflexible polymer composites with superior mechanical properties and autonomous self-healing functionality a binary filler strategy.

It is still a formidable challenge to develop ideal thermal dissipation materials with simultaneous high thermal conductivity, excellent mechanical softness and toughness, and spontaneous self-healing. Herein, we report the introduction of sandwich-like boron nitride nanosheets-liquid metal binary fillers into an artificial poly(urea-urethane) elastomer to address the above issue, which confers the composite elastomer with a unique thermal-mechanical-healing combination, including a low modulus, high in-plane thermal conductivity and high mass loading of rigid fillers but self-recoverability and room-temperature self-healing.

A Multidirectionally Thermoconductive Phase Change Material Enables High and Durable Electricity Real-Environment Solar-Thermal-Electric Conversion.

A solar thermoelectric generator (STEG) that generates electricity from sunlight is expected to be a promising technology for harvesting and conversion of clean solar energy. The integration of a phase-change material (PCM) with the STEG even more enables engines to durably generate power in spite of solar radiation flux. However, its photothermal conversion and output electricity is still limited (<15 W/m) by the PCM's deficient thermal management performance, .

Metal-Level Robust, Folding Endurance, and Highly Temperature-Stable MXene-Based Film with Engineered Aramid Nanofiber for Extreme-Condition Electromagnetic Interference Shielding Applications.

Polymer-based electromagnetic interference (EMI) shielding materials possess many irreplaceable advantages than metals, such as superior flexibility, easy processing, and low density. However, impeded by their limited mechanical properties, inferior temperature resistance and unsatisfactory electrical conductivity, it is still challenging to extend their shielding applications under some extreme conditions, i.e.

Highly Thermoconductive, Thermostable, and Super-Flexible Film by Engineering 1D Rigid Rod-Like Aramid Nanofiber/2D Boron Nitride Nanosheets.

Polymer-based thermal management materials have many irreplaceable advantages not found in metals or ceramics, such as easy processing, low density, and excellent flexibility. However, their limited thermal conductivity and unsatisfactory resistance to elevated temperatures (<200 °C) still prevent effective heat dissipation during applications with high-temperature conditions or powerful operation. Therefore, herein highly thermoconductive and thermostable polymer nanocomposite films prepared by engineering 1D aramid nanofiber (ANF) with worm-like microscopic morphologies into rigid rod-like structures with 2D boron nitride nanosheets (BNNS) are reported.

Green Production of Regenerated Cellulose/Boron Nitride Nanosheet Textiles for Static and Dynamic Personal Cooling.

Personal cooling technology using functional clothing that could provide localized thermal regulation instead of cooling the entire space is regarded as a highly anticipated strategy to not only facilitate thermal comfort and human health but also be energy-saving and low-cost. The challenge is how to endow textiles with prominent cooling effect whenever the wearer is motionless or sportive. In this study, high content of edge-selective hydroxylated boron nitride nanosheets (BNNSs) up to 60 wt % was added into a biodegradable cellulose/alkaline/urea aqueous solution, and then regenerated cellulose (RCF)/BNNS multifilaments were successfully spun in a simple, low-cost, and environmentally friendly process, which was demonstrated to serve as both static and dynamic personal cooling textile.

Gradient Polydopamine Coating: A Simple and General Strategy toward Multishape Memory Effects.

Multi shape memory polymers (multi-SMPs) exhibit many potential applications such as aerospace, soft robotics, and biomedical devices because of their unique abilities. Although many works are done to broaden the preparations of multi-SMPs, the desire to a simple and versatile strategy as well as more complex shapes still exists. Moreover, a light-induced SMP shows more advantages than a thermal-induced one in many practical working circumstances.