聚合物模板法柔韧陶瓷纳米纤维的可控制备及诱导成型机制研究

The current ceramic nanofibrous materials can not satisfy the practical applications in the fields of environment, energy, aerospace and so forth, due to their brittleness and poor mechanical properties. Herein, we will investigate the forming mechanism of flexible ceramic nanofibers induced by polymer templates and their microstructure regulation, reveal the collaborative optimization mechanism of structures and their mechanical properties. Finally, we will try to obtain flexible ceramic nanofibrous materials with excellent mechanical properties. Recently, we have prepared some soft ceramic nanofibrous materials by combining the polymer template synthesis and the electrospinning method. However, the tensile strength of the nanofibrous membranes is less than 5 MPa, which still could not meet the requirements of practical applications. Consequently, we will study the controllable fabrication and forming mechanism of the flexible ceramic nanofibers induced by polymer templates, establish the critical forming condition of the stable precursor solution with the aid of polymer templates, reveal the regulatory mechanism of hybrid precursor nanofibers, clarify the influence rule of the thermal decomposition of polymers on the microstructure of ceramic fibers. Moreover, we will find out the relationship between the structure of ceramic nanofibers and their mechanical properties, indicate the proper structure of the flexible ceramic nanofibrous membrane with optimized mechanical properties, finally obtain ceramic nanofibrous materials with the elastic modulus of single ceramic nanofiber in the range of 20 - 40 GPa, the breaking elongation of single ceramic nanofiber > 5%, the tensile strength of ceramic nanofibrous membranes > 10 MPa.

当前陶瓷纳米纤维材料普遍存在脆性大、易断裂的缺陷，难以满足其在环境、能源、航空航天等领域的实际应用需求。本项目拟研究聚合物模板诱导柔韧陶瓷纳米纤维的成型过程及纤维微观结构的调控规律，揭示材料本体结构与力学性能的协同优化机制，获得力学性能优异的陶瓷纳米纤维材料。近期申请者通过将聚合物模板法与静电纺丝技术相结合，制备出了具有一定柔性的陶瓷纳米纤维膜材料，但其拉伸断裂强度＜5MPa，仍未达到实际应用需求。为此，本项目将开展聚合物模板法柔韧陶瓷纳米纤维的可控制备及诱导成型机制研究，确立聚合物诱导均匀稳定前驱体溶液成型的边界条件，揭示聚合物/胶粒杂化纳米纤维微观结构的调控机制，明晰聚合物热分解路径对纤维微观结构的影响规律，阐明单纤维微观结构与力学性能的内在关联，确立材料具有最优力学性能时的本体结构特征，实现单纤维弹性模量20-40GPa、断裂伸长率＞5%，纤维膜拉伸断裂强度＞10MPa的目标。

本课题“聚合物模板法柔韧陶瓷纳米纤维的可控制备及诱导成型机制研究”旨在明确柔韧陶瓷纳米纤维的成型过程及纤维微观结构的调控规律，揭示纤维本体结构与力学性能的协同优化机制，实现柔韧、高强陶瓷纳米纤维在高温隔热、环境净化等领域的特效应用。从2019年初到2022年末这四年的时间里，我们开展了大量的实验研究工作：系统考察了聚合物/溶胶前驱体溶液的制备及其稳定性调控规律，阐明了聚合物/溶胶体系的稳定性调控机制，明晰了无机溶胶射流的牵伸形变及其相分离固化成纤过程，揭示了聚合物/胶粒杂化纳米纤维的成型机制；进一步地探究了杂化纳米纤维煅烧过程中聚合物热分解路径对陶瓷纳米纤维孔结构形成及胶粒迁移-成核-结晶-生长过程的作用规律，阐明了单纤维微观结构与力学特性之间的协同优化机制，建立了基于微观结构调控的陶瓷纳米纤维柔韧化调控体系，掌握了柔韧陶瓷纳米纤维的制备方法；在此基础上，我们探索了陶瓷纳米单纤维微观结构及纤维聚集体结构对材料力学性能的影响规律，实现了柔韧陶瓷纳米纤维材料力学性能的有效提升，明晰了纤维微观结构与其应用性能间的内在关联，确立了柔韧陶瓷纳米纤维具有最优应用性能时的本体结构特征。经过四年的研究，我们顺利完成了任务书中规定的任务，制备的聚合物模板法柔韧陶瓷纳米纤维实现了纤维弹性模量20~40GPa、断裂伸长率＞5%、纤维膜柔软度≤20mN、拉伸断裂强度＞10MPa的目标。项目执行期间共培养博士毕业生3名，硕士毕业生6名。发表学术论文43篇，申请发明专利5项，其中授权专利2项。本课题的完成对探索陶瓷纤维材料的柔韧机制、实现其可控制备及在高温隔热及环境净化等领域的应用具有重要意义。