微纳米纤维表面分子铁电晶态材料的结构调控与性能研究

There exist the problems that the relationship between the internal structure of molecules and ferroelectric properties is not clear, and the form of crystals can not be used in device well. In this research, molecular ferroelectric crystals will be constructed by using chiral nitronyl nitroxide, β-diketonate which both have strong structural controllability and metal ions. The relationship between chirality, functional substituents, ligand field environment of metal ions, intra/inter-molecular forces and ferroelectric properties can be clarified at the molecular level. The molecular ferroelectric crystalline thin films will also be obtained with controllable preparation on PVDF/P(VDF-TrFE) micro/nano porous fiber substrates (including the porous fiber films and the single fiber with nanoporous structures). The ferroelectric thin films can be used in kinds of functional devices. The growth, morphology of crystalline thin films and the orientation of internal dipoles can be regulated and controlled through the directivities, porous structures and diversities of fibers. The effect of component, structure, morphology and thickness of the films on ferroelectric properties will be studied. The interaction mechanism between molecular ferroelectric materials and substrates will be explained. The formation mechanism and assembling rule of the molecular ferroelectric crystalline thin films can also be clarified. The results can provide new ideas for developing of molecular ferroelectric crystalline materials, and theoretical guidance and experimental examples for achieving practical utilization level of the molecular ferroelectric materials.

针对分子内部结构与铁电性能关系不明确，晶体形态不利于在器件上应用的难题，本项目以结构可调性极强的手性氮氧自由基、β-二酮配体和金属离子构筑分子铁电晶体，从分子水平上阐明配体手性、功能取代基团、金属离子配位场环境、分子内及分子间作用力等结构因素与铁电性能之间的内在联系。并在聚偏氟乙烯、聚（偏氟-三氟乙烯）微纳米多孔纤维（包括多孔纤维膜和纳米孔结构的单根纤维）基底上可控制备分子铁电晶态薄膜，满足各种功能器件上的使用形态。通过纤维基底的方向性、多孔结构和形态的多样性进一步调控晶态薄膜的生长、形貌及内部偶极子的取向排列；研究薄膜组成、结构、形貌及厚度对铁电性能的影响；揭示分子铁电材料与基底材料间的相互影响机制；阐明分子铁电晶态薄膜的形成机理与组装规律。研究结果能够为分子铁电晶态材料的开发提供新思路；为分子铁电材料达到实际应用水平提供理论指导与实验例证。

稀土金属有机框架MOFs材料具有优异的荧光性能，荧光检测快速，简便，灵敏，但MOFs晶体材料不利于在器件上使用，在微纳米纤维表面组装稀土MOFs功能晶态材料，满足各种功能器件上的使用形态具有重要的研究意义。本研究在纤维，织物及聚合物表面成功制备了几个系列的稀土MOFs功能晶态材料，实现了智能化的颜色调控和荧光pH、T、小分子等的荧光探测，组装了比率型的荧光纳米传感器。如丝素粉体表面稀土功能晶态材料实现了对生理范围内pH的荧光探测；蚕丝纤维与织物表面键合稀土功能材料实现了智能化的颜色调控；棉布表面采用热浸压的方法可控制备了稀土MOFs功能晶态材料，实现了对Cu2+的荧光探测；利用仿生矿化的方法在温敏聚合物表面制备了稀土MOFs功能晶态材料，实现了不同溶剂的荧光识别和有机溶剂中水及微量水的快速检测；利用原子层沉积ALD技术，在蚕丝织物表面可控制备了不同纳米层厚的稀土MOFs功能晶态材料，实现了较宽范围内的温度检测。研究了MOFs薄膜组成、结构、形貌、厚度对荧光及探测性能的影响；揭示了功能晶态材料与基底间的相互影响机制。本项目研究为微纳米纤维表面分子荧光功能材料的开发提供了新的思路；为分子功能晶态材料达到实际应用水平提供了理论指导与实验例证。