Direct Laser Writing-Assisted Method for Template-Free Fabrication of Biomass-Based Porous Carbon Platelets with Uniform Size and Arbitrarily Designed Shapes

A review of hierarchical porous carbon derived from various 3D printing techniques

Hierarchical porous carbon is an area of advanced materials that plays a pivotal role in meeting the increasing demands across various industry sectors including catalysis, adsorption, and energy storage and conversion. Additive manufacturing is a promising technique to synthesize architectured porous carbon with exceptional design flexibility, guided by computer-aided precision. This review paper aims to provide an overview of porous carbon derived from various additive manufacturing techniques, including material extrusion, vat polymerization, and powder bed fusion. The respective advantages and limitations of these techniques will be examined. Some exemplary work on various applications will be showcased. Furthermore, perspectives on future research directions, opportunities, and challenges of additive manufacturing for porous carbon will also be offered.

Fabricating Graphene and Nanodiamonds from Lignin by Femtosecond Laser Irradiation

This study demonstrates a new transformation path from lignin to graphene and nanodiamonds (NDs) by femtosecond laser writing in air at ambient temperature and pressure. Graphene nanoribbon rolls were generated at lower laser power. When the laser power was high, NDs could be obtained apart from graphene and onion-like carbon intermediates. These structures were confirmed by scanning electron microscopy, X-ray diffraction, Raman spectroscopy, X-ray photoelectron spectroscopy, and high-resolution transmission electron microscopy. The effects of laser power and laser writing speed on the structure of laser-induced patterns were investigated. The results show that the laser power was more important than the writing speed for the synthesis of carbon nanoparticles, and high laser power contributed to enhanced electrically conductive performance. Therefore, the direct laser irradiation technique leads a simple, low-cost, and sustainable way to synthesize graphene and NDs and is promising for the fabrication of sensors and electric devices.

Self-Sealing Carbon Patterns by One-Step Direct Laser Writing and Their Use in Multifunctional Wearable Sensors

A combined photothermal simulation and experimental study leads to a novel internal reflection-assisted direct laser writing carbonization method (IR-DLWc), which enables in situ fabrication of carbon features/patterns that are self-sealed in the interior of a thin polyimide (PI) film in one step without additional packaging procedures. With this new method, carbon line patterns that are fully contained in a 50 μm PI film are fabricated, characterized, and evaluated for their electrical and piezoresistive performance. The self-sealing character of the carbon features created by IR-DLWc imparts them unprecedented mechanical stability/robustness as compared to those fabricated by the conventional DLWc method. Upon applying a double-writing scheme and strain-engineering treatment, the IR-DLWc-created carbon lines show significantly improved piezoresistive sensitivity with a gauge factor evaluated to be 428 in tension and 107 in compression. The high piezoresistive sensitivity, excellent dynamic response, reasonably good durability, self-sealing character, and compliant nature of the IR-DLWc generated carbon patterns make them suitable for a variety of wearable sensing applications. In this work, we demonstrated their use as a tactile sensor for sensing contact force; a functional bandage for monitoring physiological activities like swallowing, pulsing, and breathing; and a glove sensing system for finger gesture recognition.