3D Printing of Liquid‐Metal‐in‐Ceramic Metamaterials for High‐Efficient Microwave Absorption

Abstract

This work reports a gallium indium alloy (EGaIn)‐doped SiBOC ceramic that possesses a unique liquid‐metal‐in‐ceramic feature. The low‐viscosity liquid nature of gallium‐based liquid metals (Ga‐LMs) and the reactive core‐shell structure provide possibilities for phase engineering inside polymer‐derived ceramics. As a demonstration, EGaIn nanoparticles (NPs) are directly mixed with a UV‐curable ceramic precursor (UV‐PBS) to obtain a resin suitable for digital light processing 3D‐printing. After pyrolysis at 800–1200 °C, SiBOC ceramics with uniformly distributed EGaIn NP domains (Si(GaIn)BOC) are obtained. EGaIn plays a key role in promoting carbonization and preventing crack formation during the polymer‐to‐ceramic process, resulting in an increase in both ceramic yield and mechanical strength. EGaIn NPs are also found to have a core‐shell structure (EGaIn@(GaxIn1‐x)2O3@SiBOC) inside the SiBOC matrix, which significantly enhances the dielectric properties and improves the interfacial polarization. As a result, an excellent electromagnetic wave absorption performance is achieved across the C, X, and Ku bands, respectively. Through rational design, a novel metastructure design based on the Schwarz P minimal surface is proposed, which exhibits an ultrawide effective absorption band extending up to 11.36 GHz (within C‐Ku bands).

3D-Printed Liquid Metal-in-Hydrogel Solar Evaporator: Merging Spectrum-Manipulated Micro-Nano Architecture and Surface Engineering for Solar Desalination

“…Integrating the emerged 3D-printed hydrogel technique and MPNs-engineering is expected to provide a valuable design perspective and strategy for solar evaporators with highly hydratable polymeric skeletons and salt-rejecting architectures. To render evaporators compatible with photopolymerization-based 3D-printing techniques, it is essential to introduce unsaturated segments (i.e., enyl, ynyl) into the matrix and/or solar absorbers . Polymeric blocks with reactive photosensitive structures (e.g., acrylate and allyl resins) can be selected to achieve photopolymerization properties by photoinitiated free radical polymerization in a rapid time scale, speeding up the prototyping process of the 3D evaporator .…”

“…11,15 Therefore, several fascinating properties may give Ga-based liquid metals (LMs) distinct advantages in improving the photothermal and solar-to-vapor performances of solar evaporators, including excellent mechanical performance, chemical inertness, and energy storage. 20,21 However, the narrow light absorption range and inferior heat confinement of EGaIn limited its applications in the next solar-driven evaporation system. 22 Intriguingly, the photothermal conversion efficiency and broadband spectrum-absorbing ability can be further reinforced by constructing EGaIn/carbon or EGaIn/semiconductor hybrids.…”

“…To render evaporators compatible with photopolymerization-based 3D-printing techniques, it is essential to introduce unsaturated segments (i.e., enyl, ynyl) into the matrix and/or solar absorbers. 20 Polymeric blocks with reactive photosensitive structures (e.g., acrylate and allyl resins) can be selected to achieve photopolymerization properties by photoinitiated free radical polymerization in a rapid time scale, speeding up the prototyping process of the 3D evaporator. 43 To date, there are none of the 3D-printed solar evaporators that incorporate combinatorics strategies (i.e., selfsupporting architecture, a hydratable backbone with minimizing vaporization enthalpy, and maximizing actual evaporation areas) for breaking through performance bottlenecks of 3D evaporators.…”

“…Recently, the liquid matter eutectic gallium–indium (EGaIn) liquid metal has been garnering substantial interest in various fields involving photoacoustic images, photothermal conversions, and thermotics/electronics. , The localized surface plasmon resonance (LSPR) effect, which is supported by microsized EGaIn droplets, can induce prompt relaxation dynamics to a thermal excitation process during the nonradiative decay of plasmon. , Therefore, several fascinating properties may give Ga-based liquid metals (LMs) distinct advantages in improving the photothermal and solar-to-vapor performances of solar evaporators, including excellent mechanical performance, chemical inertness, and energy storage. , However, the narrow light absorption range and inferior heat confinement of EGaIn limited its applications in the next solar-driven evaporation system . Intriguingly, the photothermal conversion efficiency and broadband spectrum-absorbing ability can be further reinforced by constructing EGaIn/carbon or EGaIn/semiconductor hybrids. , Moreover, even coupling with the different nanomaterials, the solar-to-heat energy efficiency of the LM-based solar absorbers/evaporators still has space for amelioration …”

MoS2-Based Nanocomposites for Microwave Absorption: A Review

“…In recent years, with the rapid development of the 5G and 6G era of communication technology, widely used electronic products and devices receive extra attention. − At the same time, the use of electronic equipment has caused many problems, such as serious electromagnetic radiation pollution. − As shown in Figure , the electromagnetic radiation generated by various electronic devices not only surrounds people’s daily life but also brings electromagnetic interference between devices, damage to human health, and information security and other problems. − …”