Chala Tolesa Fita, Wu Chang-Mou, Chou Min-Hui, Gebeyehu Molla Bahiru, Cheng Kuo-Bing
Department of Materials Science and Engineering, National Taiwan University of Science and Technology, Taipei 10607, Taiwan, R.O.C.
Department of Fiber and Composite Materials, Feng Chia University, Taichung 40724, Taiwan, R.O.C.
Nanomaterials (Basel). 2017 Jul 22;7(7):191. doi: 10.3390/nano7070191.
In this work, novel WO/polyurethane (PU) nanocomposites were prepared by ball milling followed by stirring using a planetary mixer/de-aerator. The effects of phase transformation (WO₃ → WO → WO) and different weight fractions of tungsten oxide on the optical performance, photothermal conversion, and thermal properties of the prepared nanocomposites were examined. It was found that the nanocomposites exhibited strong photoabsorption in the entire near-infrared (NIR) region of 780-2500 nm and excellent photothermal conversion properties. This is because the particle size of WO was greatly reduced by ball milling and they were well-dispersed in the polyurethane matrix. The higher concentration of oxygen vacancies in WO contribute to the efficient absorption of NIR light and its conversion into thermal energy. In particular, WO/PU nanocomposites showed strong NIR light absorption of ca. 92%, high photothermal conversion, and better thermal conductivity and absorptivity than other WO₃/PU nanocomposites. Furthermore, when the nanocomposite with 7 wt % concentration of WO nanoparticles was irradiated with infrared light, the temperature of the nanocomposite increased rapidly and stabilized at 120 °C after 5 min. This temperature is 52 °C higher than that achieved by pure PU. These nanocomposites are suitable functional materials for solar collectors, smart coatings, and energy-saving applications.
在本工作中，通过球磨然后使用行星式混合器/脱气器搅拌制备了新型WO/聚氨酯（PU）纳米复合材料。研究了相变（WO₃→WO→WO）以及不同重量分数的氧化钨对所制备纳米复合材料的光学性能、光热转换和热性能的影响。结果发现，这些纳米复合材料在780 - 2500 nm的整个近红外（NIR）区域表现出强烈的光吸收以及优异的光热转换性能。这是因为通过球磨WO的粒径大幅减小，并且它们在聚氨酯基体中分散良好。WO中较高浓度的氧空位有助于高效吸收近红外光并将其转化为热能。特别是，WO/PU纳米复合材料表现出约92%的强烈近红外光吸收、高光热转换以及比其他WO₃/PU纳米复合材料更好的热导率和吸收率。此外，当用红外光照射含有7 wt% WO纳米颗粒浓度的纳米复合材料时，纳米复合材料的温度迅速升高，并在5分钟后稳定在120°C。该温度比纯PU达到的温度高52°C。这些纳米复合材料是适用于太阳能集热器、智能涂层和节能应用的功能材料。
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