To meet the requirement of multipurpose applications in infrared thermal camouflage and solar photothermal energy storage, we have developed a series of multifunctional composite films based on polyurethane (PU) as a flexible matrix and double-layered phase-change microcapsules as an additive. The double-layered microcapsules were first constructed by encapsulating n -docosane as a phase-change material in a titanium dioxide shell, followed by depositing a polyaniline (PANi) functional layer. Then, the microcapsules were incorporated into the PU matrix to form the composite films through in situ polycondensation . A high latent heat capacity of over 130 J g −1 was achieved by the microcapsules as a result of a high n -docosane loading. This can generate an effective thermal buffer for the composite films and thus endow them with a good thermal camouflage capability. The composite films also show good solar energy-storage performance thanks to their superior sunlight absorptivity derived from the PANi coating layer of the microcapsules. The composite films present a much higher surface temperature (68.6 °C) than pure PU film (41.9 °C) under simulated sunlight irradiation for 1488 s. In addition, the composite films exhibit a self-cleaning surface and high flexibility. Integrating the double-layered microcapsules and flexible PU matrix may provide an innovative strategy for developing flexible functional films for infrared thermal camouflage and photothermal energy storage applications .
Ming-hua Cheng,Xiang Xu,Hao-wen Zhang,Si-yu Kong,Zhe-sheng Feng,Fanbin Meng,Yan Wang
With the development of wearable devices, flexible multifunctional electromagnetic shielding (EMI) shielding materials have attracted widespread attention. In this paper, a fibrous ANF/PPy composite material was obtained by modifying aramid nanofibers (ANFs). Subsequently, the Ti 3 C 2 T x (MXene) suspension was mixed with the ANF/PPy solution, electrostatic self-assembly was performed, and an ANF/PPy/MXene composite film with a “brick (MXene)-mortar (ANF/PPy)” structure was prepared through vacuum-assisted filtration. The film has high electrical conductivity, certain mechanical tensile properties, high mechanical stability, good chemical stability, and excellent long-term stability. In addition, the film with a thickness of only 16 μm shows excellent EMI shielding (average EMI SE is 40.4 dB, absorption coefficient is 0.155, SSE/t is 36288.6 dB·cm 2 /g), dual‑driven (electrothermal and photothermal convertibility) heating and infrared thermal camouflage performance (radiation temperature is 69.4°C at a temperature of 150°C). These results show that ANF/PPy/MXene composite film is very promising in practical applications such as wearable devices, communications, high-performance heating, and infrared stealth.
Yan Biaobiao,Bao Xueming,Gao Yilei,Zhou Man,Yu Yuanyuan,Xu Bo,Cui Li,Wang Qiang,Wang Ping
Two-dimensional transition metal carbide/nitride (MXene)-based textiles have been developed in many fields; however, the high sensitivity to oxidation and weak interfacial bonding hinder their applications. Herein, we present a strategy for the preparation of a highly antioxidative MXene@gallic acid (MXene@GA, MG) hybrid dispersion, and further covalently grafted it onto carboxylated cotton fabric through interaction with metal ions (Fe 3+ ) for fabricating wearable multifunctional textiles. Due to the cross-linking effect of Fe 3+ and the remarkable antioxidant activity of natural polyphenol GA, the MG coatings firmly adhere to the textile surfaces and can withstand conventional washing, exhibiting favorable service stability and potential application prospects. Moreover, the obtained MG-decorated textile has the inherent characteristics of good breathability, moisture permeability, flexibility, and biocompatibility of the original fabric, which are conducive to the wearability of smart devices. Furthermore, by utilizing the outstanding conductivity (~ 330 S/m) and photothermal convertibility of the MG coating, the functional textile achieves high electromagnetic interference (EMI) shielding efficiency (~ 35 dB), excellent dual-driven ( Joule and solar) heating warmth retention, and infrared thermal camouflage. Due to the green and scalable preparation process, favorable durability, excellent comfort, and multifunctionality, the MG-decorated textiles are anticipated to be promising candidates for the next generation of smart wearable personal protective clothing. Graphical Abstract
危险品化学品经营许可证（带存储）