3D石墨烯气凝胶常温常压干燥制备方法及其智能特性与抗拉性能研究

Graphene monolithic structures have become one of the hotspot in carbon material studies. Three-dimensional (3D) graphene aerogels (GA) find promising applications in supercapacitors, electrode materials, gas sensors and environmental areas due to their high porosity, strong mechanical strength and excellent electrical conductivity. In order to realize the ambient drying fabrication of GA and its smart and tensile properties, this research will firstly develop an ambient drying technique to fabricate GA and then study the mechanism of its initial modulus, reduction degree and porous structure on the framework crack, solvent capillary force and material performances. Next, by in situ deposition of superparamagnetic iron oxide nanoparticles on aerogel networks, the smart GA will be fabricated with the optimal iron oxide nanoparticle loading. Then, the ultralow density, large magnetic field-induced deformation, piezoelectric, and dynamic response properties of this smart GA will be investigated. At last, the method to fabricate the carbon nanotube fiber reinforced GA and its tensile property and mechanics will be studied. This research will promote the functionalization and application of monolithic graphene, and realize a high-efficient, low-cost, safe and easy production of GA. Relevant achievements can be applied in self-sensing soft actuators, soft robot, micro-sensors and micro-switches, environmental and energy absorption/dissipation fields.

石墨烯宏观体结构是目前国际碳材料研究的热点。三维石墨烯气凝胶因其大孔隙率、优异的压缩性能及电学性能，在超级电容器、电极材料及环境污染防治等领域展现了广阔的应用前景。本项目以实现石墨烯气凝胶常温常压干燥制备，发展石墨烯气凝胶智能及抗拉特性为目标。首先，研究石墨烯气凝胶的常温常压干燥制备方法，研究材料初始弹性模量、还原程度及孔结构形貌对骨架坍缩、溶剂毛细力及材料性能的作用机理；其次，研究石墨烯气凝胶骨架原位沉积纳米超顺磁Fe3O4颗粒的制备方法及纳米Fe3O4的最佳配比，研究其超低密度、可恢复磁致大变形、压阻效应及动力响应等力学与智能特性及机理；最后，研究碳纳米管纤维增强石墨烯气凝胶的制备方法及其拉伸变形特性与机理。本项目丰富了石墨烯宏观体的研究，极大程度降低了其制备成本及难度，相关成果可应用于自感知柔性驱动器，柔性机器人，纳米开关、纳米传感器、污染物吸收和能量储存/耗散等诸多领域。

石墨烯、陶瓷气凝胶功能材料基于多尺度结构化设计，赋予传统脆性无机气凝胶材料轻质超弹、柔性传感、高热稳定性及低导热系数等优异性能，是我国《中国制造2025》和《“十三五”材料领域科技创新专项规划》重点发展的前沿领域之一。面向“军民融合”战略对高温防护气凝胶材料重大需求以及材料超轻高弹、高热稳定性和超级隔热的关键科学问题，本项目开展了石墨烯气凝胶大规模、大尺度自然干燥制备及力学性能增强，以及轻质柔韧陶瓷气凝胶系列超级隔热材料的多尺度超结构设计和碳模板辅助气相沉积制备方法研究。通过纳米厚度陶瓷微元在多尺度上结构-功能一体化设计和可控构筑，实现了具有可控有序设计的多层级宏观几何结构构型，揭示了“双曲”等超结构设计对材料负泊松比超弹变形特性的作用机理；通过气凝胶孔壁中空微观结构设计，揭示了材料负热膨胀效应对增强其热稳定性的作用机理；通过气凝胶纳米孔结构构筑，实现了其在极端环境下的超级隔热性能。本项目实现了石墨烯气凝胶可商业化自然干燥制备及力学增强，解决了传统陶瓷气凝胶脆性所带来的开裂易碎、析晶坍缩和高热导率等问题，为实现最轻质（最低固体材料密度）、柔性可穿戴传感、高热稳定性及超级绝热（最低导热系数）高性能石墨烯及陶瓷气凝胶材料，及其在国防军事和工业民用领域的广泛应用和规模化制备提供科学依据和技术支撑。