介晶结构氧化铁的合成及其性质研究

发布时间：2018-03-01 07:21

本文关键词： 多元醇法 Fe_3O_4 介晶磁共振成像造影剂　出处：《青岛科技大学》2017年硕士论文　论文类型：学位论文

【摘要】：近年来,磁性Fe_3O_4纳米颗粒由于其独特的物理化学特性,被广泛应用在生物医用,环境保护,信息存储,新能源等众多领域。而Fe_3O_4纳米颗粒的性质与其形貌结构有很大关系,不同结构形貌尺寸的Fe_3O_4颗粒往往表现出十分不同的性能,因此制备不同形貌尺寸的Fe_3O_4纳米颗粒是实现其多种应用的关键。介晶结构的纳米颗粒由于其特殊的结构以及其特殊结构所带来的物理化学特性在最近吸引了众多科学工作者的研究。目前,关于制备Fe_3O_4介晶颗粒的方法理论仍处于发展阶段,在介晶形成机理以及其应用上的许多方面还有待进一步深入研究,因此,本论文主要研究了介晶Fe_3O_4在多元醇体系中的制备以及其生长机理,并研究了其磁共振成像性质,论文主要包括以下内容:1、采用多元醇法,利用只含有氯化铁、氢氧化钠、水、乙二醇的简单体系,成功制备出了Fe_3O_4介晶颗粒,研究了铁离子浓度、氢氧化钠的用量,水的用量等反应参数对产物形貌、尺寸等性质的影响。结果表明,氢氧化钠的用量对最终是否获得Fe_3O_4物相影响较大,只有在氢氧化钠的用量与铁离子含量符合化学计量比3/1左右的情况下,反应最终才能得到高质量的纯Fe_3O_4颗粒。通过在能生成Fe_3O_4颗粒的范围内调控反应液的p H值,能够在一定范围内实现Fe_3O_4颗粒的尺寸调控。其次,水在该体系中也是必不可少的重要原料,在无水条件下,反应最终得不到Fe_3O_4物相,并且,通过调控水的加入量,也能在一定范围内调控Fe_3O_4颗粒的尺寸大小。另外,改变反应原料的混合方式可以显著改变产物的形貌尺寸,分别能得到多孔单晶类型以及小颗粒有序聚集体类型的介晶颗粒。2、对多元醇体系中的介晶Fe_3O_4的生长过程进行了深入研究。研究结果表明,Fe_3O_4在多元醇体系中的形成为非经典结晶过程,当所有原料混合均匀后,三价铁离子首先水解,生成无定形的铁的氢氧化物与乙二醇的复合物,之后,随着反应温度的升高,乙二醇溶液的还原能力开始增强,部分三价铁开始被还原成二价铁,生成了椭圆形片状结构的铁醇盐。随着反应温度的继续增加以及反应时间的推移,越来越多的三价铁被还原成二价铁,二价铁离子吸附在片状铁醇盐表面并将电子传递给醇盐内部三价铁离子,使其还原成二价铁,当醇盐内部的二价铁离子累积到一定程度,醇盐会局部溶解并结晶成核形成2 nm左右的Fe_3O_4初级颗粒,由于初级粒子表面富含羟基并结合了大量水分子,其性质与微乳液类似,一旦醇盐发生解体,可自由运动的Fe_3O_4初级颗粒为了降低体系的表面能,会自发聚集,形成较大的聚集体,随后聚集体内部的初级粒子会沿晶体学取向方向自发转动,并通过脱水消除固液界面,进一步降低系统的总能量,形成有序的介晶结构。由于溶液的p H值及体系中的羧酸根离子的存在会影响二价铁离子在醇盐表面的吸附及Fe_3O_4初级粒子的表面电荷,对Fe_3O_4初级粒子的形核及团聚过程有直接的影响,对从而最终影响产物的形貌尺寸。3、制备出了超顺磁性多孔Fe_3O_4介晶颗粒,利用多聚磷酸钠修饰其表面,使其稳定的单分散于溶液中。研究了该种介晶颗粒作为磁共振造影剂的性能,发现其具有较强的T2磁共振弛豫增强能力(r2值为435.16 mM-1 s-1),良好的生物相容性,并且在小鼠的肝脏和肾脏内具有高效快速的造影增强性能,是一类高效的T2型磁共振造影剂。
[Abstract]:In recent years, the magnetic Fe_3O_4 nanoparticles because of its unique physical and chemical characteristics, has been widely used in biomedical, environmental protection, information storage, new energy and other fields. There is a great relationship between properties and morphology of Fe_3O_4 nanoparticles, Fe_3O_4 particles of different size and shape structure often shows the performance is very different, so preparation of Fe_3O_4 nanoparticles with different morphology size is the key to realize its various applications. Nanoparticles mesomorphic structure because of its special structure and special structure caused by the physical and chemical properties in recent research has attracted many researchers. At present, the theory about the preparation method of Fe_3O_4 dielectric crystal particles is still in the stage of development in many ways, mesocrystal formation mechanism and its application remains to be further study. Therefore, this paper mainly studies the mesogenic Fe_3O_4 in polyol In the system of the preparation and the growth mechanism, and to study the magnetic resonance imaging properties, the main contents are as follows: 1 by polyol method using only containing ferric chloride, sodium hydroxide, water, simple system of ethylene glycol, successfully prepared Fe_3O_4 crystal particles, the iron ion concentration, sodium hydroxide the amount on the morphology of reaction parameters such as quantity of water, the influence of size and other properties. The results showed that the amount of sodium hydroxide on the final phase of Fe_3O_4 is affected only in the amount of iron ions and sodium hydroxide in stoichiometric 3/1. Reaction to obtain pure Fe_3O_4 particles with high quality. By adjusting the reaction solution p value in the range of H can generate Fe_3O_4 particles, can realize the size control of Fe_3O_4 particles in a certain range. Secondly, the water in the system is also essential The important raw materials, under anhydrous conditions, the reaction will end up getting the Fe_3O_4 phase, and, by adding water volume control, also can be in a certain range to control the size of the Fe_3O_4 nanoparticles size. In addition, the mixed mode change of reaction materials can significantly change the morphology and size of products, which can get the mesogenic.2 particles porous single crystal the type of small particles and aggregates type, the growth process of the mesogenic Fe_3O_4 polyol in the system were studied. The results show that the Fe_3O_4 formation in the polyol system in a non classical crystallization process, when the raw materials are mixed evenly, ferric ion is first hydrolyzed, after complex formation no amorphous iron hydroxide and ethylene glycol, with the reaction temperature, the reduction ability of ethylene glycol solution began to increase, some trivalent iron began to be reduced to two valent iron, generate elliptical Ferrite structure. With the reaction temperature and reaction time on continue to increase, more and more ferric iron was reduced to two iron, two iron ions in the adsorption of flake iron alkoxide and the electron transfer to the surface alkoxide internal ferric ion, it reduced to two iron, when the price of two iron alkoxide internal accumulated to a certain extent, alcohol salt will dissolve and local Fe_3O_4 primary particle nucleation formed about 2 nm, the primary particles are hydroxyl groups on the surface and the combination of a large number of water molecules, the properties of emulsion and similar, once the alkoxide and Fe_3O_4 primary particles in order to reduce the freedom of movement system of surface energy, spontaneous aggregation, formation of large aggregates, then primary particles inside the aggregates along the crystallographic orientation direction of spontaneous rotation, and through the elimination of dehydration of solid-liquid interface, to further reduce the total energy of the system, form A mesomorphic structure orderly. Due to the presence of carboxylate ions in solution P and H value in the system will affect the surface charge of two valent iron ions in the alkoxide surface adsorption and Fe_3O_4 primary particles, directly affects the nucleation and agglomeration of Fe_3O_4 primary particles, which ultimately affect the morphology and size of.3 the product, prepared superparamagnetic Fe_3O_4 porous dielectric crystal particles, using sodium polyphosphate modified on the surface, the stability of the single dispersed in solution was studied. The mesomorphic properties of particles as magnetic resonance contrast agent, we find that it has T2 strong magnetic resonance relaxation enhancement ability (R2 = 435.16 mM-1 s-1), good biocompatibility, and has a fast and efficient performance in contrast enhancement of liver and kidney, is a kind of high efficient T2 type magnetic resonance contrast agent.

【学位授予单位】：青岛科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TQ138.11

【参考文献】