Basic Study on Novel Molecule-Based Magnetic Polymers and Homogeneous Magnetic Fluids

新型分子基磁性聚合物和均质磁性流体的基础研究

• 批准号: 0755763
• 负责人: Chang Han
• 金额: $ 31.44万
• 依托单位: University of Akron
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-02-01 至 2011-01-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0755763&HistoricalAwards=false
• 关键词: Basic; Study; Novel; Molecule; Based

CBET-0755763, HanThis research focuses on the design, synthesis, and characterization of molecule-based magnetic polymers having high Curie temperature (Tc). A series of monomers having tetracyano units or stable radicals (e.g., verdazyl radical or thioaminyl radical) for electron acceptor will be synthesized and each of the monomers will be reacted with a ferrocene- and biferrocene-containing monomer with long flexible side chains to obtain molecule-based magnetic polymers. Such polymers will form intramolecular exchange interactions through covalent bonding between the strong electron donor of ferrocene or biferrocene units along the macromolecular chains with the strong electron acceptor of tetracyano unit or stable radical. The intermolecular super exchange coupling will occur due to the polarization of both ferrocene (or biferrocene) units and tetracyano units (or stable radicals), and the entanglement of macromolecular chains will facilitate the expansion of one-dimensional spin coupling into a three-dimensional one. The magnetic properties of the polymers synthesized will be characterized using a magnetometer. X-ray diffraction will be employed to confirm that the polymers synthesized do not contain any impurities such as iron oxide, and electron spin resonance spectrometry will be employed to confirm the presence of spin interactions in the polymers synthesized. Owing to the presence of long flexible side chains on the ferrocene- or biferrocene-containing monomers used, such molecule-based magnetic polymers are expected to be soluble in common solvents. Such a prospect will ?open the door? to the development of a new generation of homogeneous magnetorheological (MR) fluids, quite different from the conventional MR fluids in current industrial use that are suspensions of very heavy magnetic particles (iron oxide or ferrite) in a light carrier liquid which are subject to serious problems of sedimentation and aggregation. The PI will investigate the fundamentals of the rheological behavior of a new generation of homogeneous MR fluids that will be prepared from the polymers synthesized in this research.INTELLECTUAL MERITAlthough small-molecule organic magnets having low Curie temperature (Tc) (much lower than room temperature) have been reported, during the past three decades many research groups have tried to develop truly molecule-based magnetic polymers having high Tc (much higher than room temperature). This research, if successful, will pave new frontiers in polymer synthesis, electronic structure chemistry, and materials chemistry, as well as stimulate theorists to develop new theory for magnetisms of macromolecules, since the currently available theories of magnetism deal with small-molecule organic magnets. High Tc molecule-based magnetic polymers may exhibit numerous desirable properties, including solubility, processability, and synthetic tenability, and could have practical applications. This project could provide new insights into how to design molecule-based magnetic materials having high Tc. It could also fundamentally advance the coordination chemistry of stable free radicals.BROADER IMPACTSThe research could have a broad impact on several scientific engineering disciplines including polymer chemistry, organometallic/coordination chemistry, condensed matter physics, and rheology for the development of a new theory for homogeneous MR fluids. Successful completion of the research project could lead to new method(s) for the synthesis of novel molecule-based magnetic polymers having high Tc, which do not exist at present, and can have an impact on manufacturing processes for a new generation of novel magnetic polymers and also the automotive industry that makes extensive use of magnetorheological fluids. The research will be highly interdisciplinary; graduate students will be exposed to a wide range of research experiences in the design and synthesis of novel polymers and their characterization, which will provide breadth and flexibility for their future careers.

CBET-075576​​3，Hanthis Research的重点是具有高咖喱温度（TC）的基于分子的磁聚合物的设计，合成和表征。 将合成一系列具有四环单元或稳定的自由基（例如，维达唑自由基或硫氨基自由基）的电子受体的单体，并且将合成用于电子受体的单体，并且每个单体都将与二甲茂铁和双二十二烯的单体链链链链链式链链反应。这样的聚合物将通过与大分子链的强二苯甲酸单元或稳定的自由基的强电子受体或稳定的电子受体之间的强二二二甲基二苯或双二苯基单位之间的共价键形成分子内交换相互作用。 由于二茂铁（或双二世）单位和四酰基单元（或稳定的自由基）的极化，将发生分子间的超级交换耦合，并且大分子链的纠缠将促进一维旋转螺旋成三维式旋转的扩展。 合成的聚合物的磁性特性将使用磁力计表征。 将采用X射线衍射来确认合成的聚合物不含氧化铁等杂质，并且将采用电子自旋谐振光谱法来确认合成的聚合物中存在自旋相互作用的存在。 由于所用的二茂铁或双二世型单体存在长柔性侧链，因此，这种基于分子的磁聚合物有望在常见溶剂中溶于溶解性。 这样的前景会打开门？开发新一代均质磁化（MR）流体，与当前工业用途中常规的MR流体截然不同，这些液体是在轻型载体液体中非常重的磁性颗粒（氧化铁或铁氧体）的悬浮液，这些悬浮液遇到了严重的沉积和聚集问题。 PI将研究新一代同质MR流体的流变行为的基本原理，这些液体将从这项研究中合成的聚合物制备。在过去的三十年中，在过去的三十年中，许多研究组都高得多的磁性磁铁（在过去的三十年中，都有很多基于磁性的磁性磁性，itelectual Meritalthoutal Meritalthougal Meritalthougal Meritalthougal Meritalthougal Meritalther smalitthy小分子有机磁铁（比室温低得多）（比室温低得多）。 这项研究，如果成功的话，将在聚合物合成，电子结构化学和材料化学方面铺平新的边界，并刺激理论家为大分子的磁性开发新的理论，因为当前可用的磁性理论与小分子有机磁铁有关。 高TC分子的磁性聚合物可能表现出许多理想的特性，包括溶解度，加工性和合成性允许性，并且可能具有实际应用。 该项目可以为如何设计具有高TC的基于分子的磁性材料提供新的见解。它还可以从根本上推进稳定自由基的协调化学。BRODER对研究的影响可能会对几个科学工程学科产生广泛的影响，包括聚合物化学，有机金属/协调化学，冷凝物理学和流变学来开发新理论的同质MR MR FLOID。该研究项目的成功完成可能会导致新的方法，用于合成具有高TC的新型基于分子的磁聚合物，目前尚不存在，并且可能会影响新一代新一代新型磁性聚合物的制造过程，以及使磁流理流体广泛使用的汽车行业。 这项研究将是高度跨学科的；研究生将在新型聚合物的设计和综合方面接触广泛的研究经验，这将为他们的未来职业提供广度和灵活性。