外场诱导下纯石墨烯纺丝液中片层的定向排列与纤维性能的关系

The high charge transfer of graphene layers, can be maintained in neat graphene fiber, which possesses good weavability, resulting in the widespread applications of research and development of flexible devices. The key point of properties and stability of properties of flexible devices is the control of alignment degree of graphene in axis direction. Unlike the strategy of control of packing structure of graphene layers in solidification process by other researchers, we utilize electric field to regulate the remove and orientation of polarized graphene layers in gels and precipitate the formation of uniformed precursor structure with preliminary alignment on the basis of centrifugal filtration of layers, and meanwhile cone spinning duct was chosen to keep the stability of precursor structure, resulting in the realization of spinning stability and control of axis structure of fiber. Moreover, with the help of the dynamics calculations of diffusion model of electron between graphene layers, the transfer mechanism of electron on the fiber will be analyzed. In our study, the rheological behavior of graphene gels and rotation dynamics of graphene layers under external field will be explored, and the relationship of effective connection of conjugated system and transfer speed of electron will be constructed. Such study can provide the experience of development of flexible graphene fiber with controlled alignment structure and excellent properties.

以纯石墨烯为单组分纺制的纤维具有织造成型性，且保留了石墨烯片层的高电荷转移能力，可广泛应用于柔性导电器件的设计与开发。控制石墨烯片层沿纤维轴向排列的规整度是保证导电器件性能及性能稳定性的关键。区别于其他研究者仅在纤维成纤凝固阶段对片层堆砌结构进行控制的策略，本项目在石墨烯片层离心分层筛选基础上，拟通过外场对带有负电荷极化层的石墨烯片层的分布与转向进行调控，促使片层在纺丝液中预先形成初具规律排布且均匀的前驱结构，并利用锥型纺丝孔保持所形成前驱结构的稳定性，从而达到后期稳定纺丝与控制轴向结构的目的。此外，结合电子在石墨烯片间扩散模型的动力学计算结果，深刻理解电子在纤维上的传递机理。通过本项目的实施，明确影响纺丝液流变行为的主要因素及外场诱导下石墨烯片层转向的动力学原理，阐明纤维上共轭体系的有效搭接与界面电子传递速度间的联系，为开发结构有序可控、性能优异的柔性纯石墨烯纤维提供借鉴。

利用湿法纺丝的策略制备纯石墨烯纤维，具备优异导电性的同时，还体现了柔性特征，在航空、航天、消防、军事等领域应用前景广泛，目前该项技术已经可以进行工业规模化纺制，是近年纤维材料领域的研究热点之一。本课题分别利用外场诱导纺丝和调控自组装的方法，制备了具有弹性、电催化、热敏性或者压电等性能的智能石墨烯纤维，并且在棉纤维表面制备取向排列的石墨烯组装层，较为系统地研究了石墨烯片层的堆砌、吸附与组装规律，并探讨了石墨烯转向调控机制，基本实现了石墨烯片层的调控组装与性能设计。系统表征了石墨烯纤维的电力学性能、温度响应性、压电性能、电催化性能等，结果表明，外场诱导时，磁化的石墨烯片层进行规律转向并实现了由S型堆砌结构向I型堆砌结构的转变，且制备的石墨烯纤维表现出优异的柔弹性，拉伸延展率达到了51.97%，且纤维的蠕变回复率超过了75%。除了电力学性能之外，制备的石墨烯纤维表现出更好的温度、压力灵敏性以及对染料的电催化性能。通过本课题的研究，掌握了无机片层在外场调控下组装的调控机制和结构变化对材料性能的影响规律，可为设计与开发高性能、新功能纤维材料提供借鉴。