带电荷纳米线诱导无机纳米材料的生长及其性能研究

发布时间：2019-03-29 11:04

【摘要】：有机体内的生物矿物无论在多级分层结构上还是在性能上都具有着很大的优越性。运用生物矿化的基本原理制备具有优越性能的新型功能材料已成为化学和材料科学领域的重要挑战之一。一维纳米结构在尺度和维度上类似于生物体内能够诱导生物矿物成核生长的超分子或其组装体。基于此,在本论文中选用各种表面带有电荷的一维纳米线为前驱物,主要讨论了如何利用无机纳米线诱导生物矿物的成核生长并以其为模板诱导制备新型功能材料。取得的主要研究结果如下：1.建立了由超细无机纳米线诱导无定型碳酸钙(ACC)生长组装的合成体系,成功制备了ACC@Te纳米线和ACC纳米片。在该体系中,以聚乙烯吡咯烷酮(PVP)分子稳定的碲(Te)纳米线为诱导剂,分别通过气相扩散法和溶剂热法诱导组装ACC纳米颗粒。值得注意的是,纳米线表面电荷对于在形成尺寸均一的ACC@Te纳米线和ACC纳米片的过程中起到了至关重要的作用。通过调节Te纳米线的浓度、混合溶剂的体积比和Te纳米线的直径,探讨了ACC@Te纳米线和ACC纳米片的形成机理。此外,利用ACC纳米片作为组装单元可以成功制得具有显著韧性的海藻酸钠/ACC仿生复合薄膜；ACC纳米片上大量存在PVP分子因而可以负载磁性纳米粒子,制得具有磁性的ACC功能材料。这种利用超细纳米线诱导无定型生物矿物组装的方法可以扩展至其他无机碳酸盐材料的控制合成,也为深入理解生物矿化的机理提供了一些线索。2.创立了一种利用硬硅酸钙纳米线诱导合成无定型金属氢氧化物纳米纤维的通用方法。运用这种方法合成了组分可控的一系列无定型二元金属氢氧化物纳米纤维。对金属氢氧化物进行热处理,还可制得相应的金属氧化物纳米纤维。这一方法还可扩展到其他无定型金属氢氧化物材料控制合成过程,所制备的金属氢氧化物纳米纤维和金属氧化物纳米纤维有望在众多领域中具有潜在的应用。3.发展了一种硬硅钙石纳米线诱导制备赤铁矿微米球介观晶体的新方法。将硬硅酸钙纳米线与氯化铁溶液混合后,经水热反应整个反应系统被加热至160℃,此后,初级赤铁矿纳米组装单元定向组装,最后获得尺寸均一、高度结晶的赤铁矿介观晶体。在此矿化体系中,可以通过调节纳米线和FeCl3的浓度分别调节赤铁矿介观晶体的尺寸和形貌。这种生物矿化模拟方法为合成其他介观材料提供了一种新的策略。4.研究了含镁无定形碳酸钙(Mg-ACC)在乙醇/水混合溶剂中相转变过程,此过程反应条件温和且不添加任何有机添加剂。调节温度、乙醇/水体积比以及Mg-ACC的初始浓度可以实现对产物的热力学和动力学调节。此外,55℃时4.5mMMg-ACC在乙醇-水混合溶剂中(乙醇／水体积比为3/2)陈化24 h,可获得文石相微椭球体,这种微椭球体由文石相纳米纤维组成。这项工作可能会为理解自然界中CaCO3的矿化过程提供一些有用的线索,也可以为工业生产不同形貌的碳酸钙提供方法指导。
[Abstract]:The biological minerals in the organism have great superiority whether in a multi-stage layered structure or in performance. The application of the basic principle of biomineralization to prepare new functional materials with superior performance has become one of the important challenges in the field of chemistry and material science. The one-dimensional nanostructures are similar in size and dimension to supermolecules or their assemblies capable of inducing the nucleation and growth of biological minerals within the organism. Based on this, a kind of one-dimensional nano-wire with charge on various surfaces is used as the precursor in this paper. It mainly discusses how to use the inorganic nano-wire to induce the nucleation and growth of the biological minerals and to use it as a template to induce the preparation of new functional materials. The main results obtained are as follows:1. The synthesis system of the growth and assembly of amorphous calcium carbonate (ACC) induced by ultra-fine inorganic nano-wire was established, and the ACC@Te nano-wire and the ACC nano-sheet were successfully prepared. In the system, ACC nanoparticles were induced by a gas-phase diffusion method and a solvothermal method, respectively, as an inducer. It is to be noted that the nanowire surface charge plays a critical role in the process of forming a size-uniform ACC@Te nanowire and an ACC nanosheet. By adjusting the concentration of the Te nanowire, the volume ratio of the mixed solvent and the diameter of the Te nanowire, the formation mechanism of the ACC@Te nano-wire and the ACC nanosheet is discussed. In addition, that ACC nanosheet can be used as an assembly unit to successfully prepare the sodium alginate/ ACC biomimetic composite film with significant toughness; and a large amount of the PVP molecule on the ACC nano sheet can load the magnetic nanoparticles to prepare the ACC functional material with magnetism. The method can be extended to the control and synthesis of other inorganic carbonate materials, and provides some clues for the in-depth understanding of the mechanism of the biomineralization. The invention discloses a general method for synthesizing amorphous metal hydroxide nano-fiber by using a hard calcium silicate nanowire. A series of amorphous binary metal hydroxide nano-fibers with controllable components are synthesized by using the method. The metal hydroxide is heat-treated, and the corresponding metal oxide nano-fiber can be prepared. The method can also be extended to other amorphous metal hydroxide materials to control the synthesis process, and the prepared metal hydroxide nano-fiber and the metal oxide nano-fiber are expected to have potential application in many fields. A new method for preparing hematite micro-sphere mesoscopic crystal is developed. After the hard calcium silicate nano-wire and the ferric chloride solution are mixed, the whole reaction system is heated to 160 DEG C by a hydrothermal reaction, and after that, the primary hematite nano assembly unit is directionally assembled, and finally, a highly crystalline hematite mesoscopic crystal is obtained. In the mineralization system, the size and morphology of the hematite mesoscopic crystals can be adjusted by adjusting the concentration of the nanowires and the FeCl3, respectively. The biological mineralization simulation method provides a new strategy for the synthesis of other mesoscopic materials. The phase transition of magnesium-containing amorphous calcium carbonate (Mg-ACC) in ethanol/ water mixed solvent was studied. The reaction conditions were mild and no organic additives were added. The temperature, ethanol/ water volume ratio and the initial concentration of Mg-ACC can be used to adjust the thermodynamic and kinetic properties of the product. In addition, at 55. degree. C., 4.5 mMMg-ACC was aged for 24 h in an ethanol-water mixed solvent (ethanol/ water volume ratio of 3/2). This work may provide some useful clues to the understanding of the mineralisation of CaCO3 in nature and can also provide methodological guidance for the production of different shapes of calcium carbonate.
【学位授予单位】：中国科学技术大学
【学位级别】：博士
【学位授予年份】：2015
【分类号】：TB383.1

【相似文献】