Department of Mechanical Engineering , Ulsan National Institute of Science and Technology , 50 UNIST-gil , Ulsan , Republic of Korea , 44919.
Nano Lett. 2018 Nov 14;18(11):6731-6739. doi: 10.1021/acs.nanolett.8b02408. Epub 2018 Oct 11.
Thermotherapy is a widespread technique that provides relief for muscle spasms and joint injuries. A great deal of energy is used to heat the surrounding environment, and heat emitted by the human body is wasted on our surroundings. Herein, a woven Kevlar fiber (WKF)-based personal thermal management device was fabricated by directly growing vertical copper-nickel (Cu-Ni) nanowires (NWs) on the WKF surface using a hydrothermal method. The treated WKF was combined with reduced graphene oxide (rGO) dispersed in polydimethylsiloxane (PDMS) to form composites using vacuum-assisted resin transfer molding (VARTM). This WKF-based personal thermal management system contained a conductive network of metallic NWs and rGO that promoted effective Joule heating and reflected back the infrared (IR) radiation emitted by the human body. It thus behaved as a type of thermal insulation. The Cu-Ni NWs were synthesized with a tunable Ni layer on Cu core NWs to enhance the oxidation resistance of the Cu NWs. The combined effect of the NW networks and rGO enabled a surface temperature of 70 °C to be attained on application of 1.5 V to the composites. The CuNi-WKF/PDMS provided 43% more thermal insulation and higher IR reflectance than bare WKF/PDMS. The absorbed impact energy and tensile strength was highest for the CuNi- and rGO-integrated WKF/PDMS samples. Those Cu-Ni NWs having higher Ni contents displayed better mechanical properties and those with higher Cu contents showed higher Joule heating performance and IR reflectivity at a given rGO loading. The composite shows sufficient breathability and very high durability. The high flexibility of the composites and their ability to generate sufficient heat during various human motions ensures their suitability for wearable applications.
热疗是一种广泛应用的技术，可缓解肌肉痉挛和关节损伤。大量的能量用于加热周围环境，而人体散发的热量则浪费在周围环境中。在此，通过水热法在编织芳纶纤维（WKF）表面直接生长垂直的铜-镍（Cu-Ni）纳米线（NWs），制备了基于 WKF 的个人热管理装置。将处理过的 WKF 与分散在聚二甲基硅氧烷（PDMS）中的还原氧化石墨烯（rGO）结合，使用真空辅助树脂传递模塑（VARTM）形成复合材料。这种基于 WKF 的个人热管理系统包含了金属 NWs 和 rGO 的导电网络，促进了有效的焦耳加热，并反射了人体发出的红外（IR）辐射。因此，它表现出一种隔热性能。通过在 Cu 核 NWs 上合成具有可调 Ni 层的 Cu-Ni NWs，增强了 Cu NWs 的抗氧化性。NW 网络和 rGO 的共同作用使得在复合材料上施加 1.5V 时可以达到 70°C 的表面温度。CuNi-WKF/PDMS 比裸 WKF/PDMS 提供了 43%更多的热绝缘和更高的 IR 反射率。CuNi-和 rGO 集成的 WKF/PDMS 样品具有最高的吸收冲击能量和拉伸强度。那些 Ni 含量较高的 Cu-Ni NWs 表现出更好的机械性能，而那些 Cu 含量较高的 Cu-Ni NWs 在给定的 rGO 负载下表现出更高的焦耳加热性能和 IR 反射率。该复合材料透气性好，耐久性高。复合材料的高柔韧性及其在各种人体运动中产生足够热量的能力，确保了它们在可穿戴应用中的适用性。
