介孔有机硅杂化纳米材料的设计合成与性质研究

发布时间：2018-10-23 12:23

【摘要】：自M41S系列介孔材料于1992年被合成以来,介孔氧化硅材料便一直是科学家的研究热点。介孔氧化硅纳米材料由于具有纳米级的尺寸、独特的孔结构以及较好的稳定性,已经被广泛的应用到不同的科学研究领域中。介孔有机硅杂化纳米材料兼具了有机材料和无机介孔材料的双重功能,如较高的比表面积、较大的孔尺寸、均一可调的孔径、易于修饰的内/外表面以及有机无机组分均匀的分布在整个骨架等,在生物医学、染料担载与释放、催化等领域具有广泛的应用前景。本论文主要是围绕设计合成结构新颖的介孔有机硅杂化纳米材料展开,利用两种不同的合成策略设计合成了具有不同形貌的介孔有机硅杂化纳米材料。一是利用简单的乙基基团桥连的有机硅前驱体设计合成具有不同对称性、不同孔道结构的介孔有机氧化硅纳米材料;二是利用含有氨基、巯基的有机硅前驱体与无机硅前驱体正硅酸乙酯共同水解与聚合,设计合成具有不同形貌的有机功能化的介孔氧化硅纳米材料。本论文主要取得了以下研究成果:1.设计了一种简单、可控的对称/非对称包覆的方法,通过使用核-壳(core-shell)结构的Au@SiO_2纳米粒子作为种子,制备了具有不同形貌的周期性介孔有机氧化硅(PMO)纳米结构,包括非对称(Janus)结构的AuPMO、蛋黄-蛋壳(yolk-shell)结构的Au@PMO以及蛋黄-双壳(yolk-double shell)结构的Au@PMO/m SiO_2纳米粒子。在反应过程中,氨水首先作为碱性催化剂促进有机硅前驱体的水解与聚合;随后氨水作为刻蚀剂选择性的溶解Au@SiO_2纳米粒子中的SiO_2壳形成中空的纳米结构。得到的三种纳米粒子均具有较高的比表面积、较大的孔体积以及可调的空腔结构。并且,制备的AuPMO和Au@PMO纳米粒子对过氧化氢的分解和4-硝基酚的还原反应均表现了良好的催化活性。由于独特的纳米结构以及有机-无机复合的组成,使得Janus结构的PMO和中空结构的(hollow)PMO纳米粒子均表现了极低的溶血活性,为介孔有机氧化硅纳米材料在生物医药领域的进一步应用提供了潜力。2.利用硫代甜菜碱和十二烷基硫酸钠作为双模板剂,通过调节反应体系中乙醇的体积分数,实现了介孔有机氧化硅纳米粒子从单介孔向双介孔结构的转变。核-壳结构的双介孔有机氧化硅纳米粒子在外壳上具有较小的介孔(4.0 nm),在内核中具有花瓣状的较大介孔(46 nm)。由于独特的多级介孔结构,双介孔有机氧化硅纳米粒子在客体担载的应用中表现出了较高的担载量和较缓慢的释放速度。这主要是因为内核上的较大介孔能够为客体分子提供较大的存储空间,而外壳上的较小介孔作为天然的阀门使得存储在内部的客体分子能够缓慢的释放。并且,单介孔和双介孔有机氧化硅纳米粒子均表现出了较低的细胞毒性和良好的细胞浸润性。3.设计了一种简单、通用的类发芽生长的方法,成功地合成了具有有机-无机复合组成的非对称(Janus)结构的介孔氧化硅纳米粒子。整个合成过程使用周期性介孔有机氧化硅(PMO)纳米粒子作为种子,介孔二氧化硅(SiO_2)作为分枝在PMO纳米粒子的表面生长。通过简单的调节反应体系中无机硅源正硅酸乙酯的加入量,可以很好的控制Janus介孔氧化硅纳米粒子中SiO_2分枝的长度和数量。另外,Janus介孔氧化硅纳米粒子的不同区域很容易被功能化不同的有机基团,可以将PMO纳米粒子修饰氨基基团(-NH_2),将SiO_2分枝上修饰磺酸基团(-SO_3H),这样便设计合成了具有酸碱双催化活性的Janus介孔氧化硅纳米粒子。进一步的催化实验也表明双功能化的Janus介孔氧化硅纳米粒子在酸-碱脱保护的Henry串联反应中表现出了优良的催化活性。4.利用简单的蛋黄-蛋壳(yolk-shell)结构的纳米粒子作为基质,成功地设计合成了类石榴形介孔氧化硅纳米粒子,它是由多个金属内核和功能化巯基基团的介孔氧化硅外壳构成。能够成功地嵌入不同种类的金属纳米粒子(Pd、Pt、Au)作为类石榴形纳米结构中的内核,并且可以很容易的将外壳上的巯基基团氧化成酸性的磺酸基团。不同于简单的yolk-shell结构的纳米粒子,类石榴形的纳米粒子具有其独特的结构和化学组成特征,可以用作纳米反应器,在合成苯并咪唑衍生物的串联反应中表现出了良好的双功能催化活性及循环稳定性。另外,类石榴形纳米粒子中的内核和外壳也分别在加氢还原4-甲氧基-硝基苯以及苯二甲缩醛的脱保护反应中表现出了优良的催化活性。
[Abstract]:Since its synthesis in 1992, mesoporous silica material has been a hot spot for scientists. The mesoporous silica nano-materials have been widely applied to different fields of scientific research because of its nano-scale, unique pore structure and better stability. The mesoporous organic silicon hetero-nano material has the dual functions of organic materials and inorganic mesoporous materials, such as higher specific surface area, larger pore size, uniform adjustable pore size, easy-to-modify inner/ outer surfaces and uniform distribution of organic and inorganic components on the whole framework and the like, and has wide application prospect in the fields of biomedicine, dye loading and release, catalysis and the like. This paper mainly focuses on the design and synthesis of a novel mesoporous organosilicone heterogenous nano-material, which is designed and synthesized with two different synthetic strategies. The method comprises the following steps of: designing a mesoporous organic silicon oxide nano material with different symmetry and different pore channel structures by using a simple ethyl group bridging organic silicon precursor; and II, jointly hydrolyzing and polymerizing a silicon precursor containing an amino group and a hydroxyl group and an inorganic silicon precursor, Organic functionalized mesoporous silica nano-materials with different morphology are designed and synthesized. The thesis mainly gains the following research results: 1. A simple and controllable symmetric/ asymmetric coating method is designed. By using the core-shell structure of the Au@SiO_2 nanoparticles as seeds, the periodic mesoporous organic silicon oxide (PMO) nanostructures with different morphologies are prepared, including the AuPMO of the asymmetric (Janus) structure. The Au@PMO of egg yolk-shell structure and the Au@PMO/ m SiO _ 2 nanoparticles of yolk-double shell structure. During the reaction process, ammonia water is first used as an alkaline catalyst to promote the hydrolysis and polymerization of the organic silicon precursor, and then the ammonia water is used as an etching agent to selectively dissolve the SiO2 shell in the Au@SiO_2 nano-particles to form a hollow nano structure. The obtained three kinds of nano-particles have higher specific surface area, larger pore volume and adjustable cavity structure. In addition, the prepared AuPMO and Au@PMO nanoparticles showed good catalytic activity for the decomposition of hydrogen peroxide and reduction of 4-nitrophenols. Due to the unique nanostructure and the composition of the organic-inorganic composite, the PMO and hollow PMO nanoparticles of the Janus structure all exhibit extremely low hemolysis activity, and provide the potential for further application of the mesoporous organic silicon oxide nano-materials in the biological medicine field. By adjusting the volume fraction of ethanol in the reaction system, the transformation of the mesoporous organic silicon oxide nanoparticles from the single mesoporous to the dimesopore structure is achieved by adjusting the volume fraction of ethanol in the reaction system. The double-dielectric porous organic silicon oxide nanoparticles of the core-shell structure have smaller dielectric holes (4.0 nm) on the shell, and have petal-shaped larger dielectric holes (46 nm) in the core. Due to the unique multi-stage dielectric hole structure, the double-porous organic silicon oxide nanoparticles exhibit higher loading and slower release speed in the application of object loading. This is mainly because the large dielectric holes on the inner core can provide large storage space for guest molecules, while smaller dielectric holes on the shell serve as natural valves so that guest molecules stored inside can be released slowly. Moreover, both single and dimesopore organic silicon oxide nanoparticles exhibited lower cytotoxicity and good cell infiltrations. In this paper, a simple and universal method of germination growth is designed, which successfully synthesizes the mesoporous silica nanoparticles with an organic-inorganic composite structure. In the whole synthesis process, periodic mesoporous organic silicon oxide (PMO) nanoparticles were used as seeds, and mesoporous silica (SiO _ 2) was used as a branch to grow on the surface of PMO nanoparticles. The length and quantity of SiO _ 2 branch in Janus mesoporous silica nano-particles can be well controlled by the addition of the inorganic silicon source n-ethyl silicate in the simple regulation reaction system. In addition, the different regions of the Janus mesoporous silica nanoparticles are easily functionalized with different organic groups, the PMO nanoparticles can be modified with amino groups (-NH _ 2), and the sulfonic acid groups (-SO _ 3H) are modified on the SiO _ 2 branch. Janus mesoporous silica nanoparticles with acid-base double catalytic activity are designed in this way. Further catalytic experiments also show that the double functionalized Janus mesoporous silica nanoparticles exhibit excellent catalytic activity in the acid-base deprotected Henry series reaction. By using the simple egg yolk-shell structure nanoparticles as the matrix, it is successfully designed to synthesize the garnet-shaped mesoporous silica nanoparticles, which is composed of a plurality of metal cores and a mesoporous silicon oxide shell of a functionalized poly-silicon group. different kinds of metal nanoparticles (Pd, Pt, Au) can be successfully embedded as the core in the garnet-like nano-structure, and the hydroxyl groups on the shell can be easily oxidized to acidic sulfonic acid groups. Different from the simple yolk-shell structure, the garnet-like nanoparticles have their unique structure and chemical composition, can be used as the nano-reactors, and show good double-functional catalytic activity and cyclic stability in the series reaction of the synthesized heteropoly acid derivatives. In addition, the core and the outer shell in the pomegranate-shaped nano-particles also show excellent catalytic activity in the deprotection reaction of the hydrogenation reduction 4-methoxy-nitrobenzene and the phenyldimethylal, respectively.
【学位授予单位】：吉林大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：TB383.1

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