本文選題：自組裝　切入點：溶劑　出處：《南京大學(xué)》2017年碩士論文　論文類型：學(xué)位論文

【摘要】：納米材料的自組裝是當今納米科學(xué)領(lǐng)域的研究熱點之一,這是因為自組裝不僅是納米材料的一種生長機制,而且可以用于構(gòu)造具有特定集體性質(zhì)的納米超結(jié)構(gòu)。自組裝是一個十分復(fù)雜的過程,會受制于多種因素,包括自組裝單元的形狀,電偶極矩、磁偶極矩、氫鍵、范德瓦耳斯力等各種驅(qū)動力,以及外加電場、磁場、光等的調(diào)節(jié)。目前,關(guān)于自組裝機理的研究仍然在不斷深入地開展著。我們考慮,在溶液中,溶劑和離子是兩種重要的物質(zhì),并且與納米晶之間存在吸附/脫吸附、氫鍵、靜電力等多種相互作用,因而可以推斷它們會對溶液中納米材料的自組裝產(chǎn)生重要影響。本文以堿式醋酸鋅納米片到ZnO的轉(zhuǎn)變與自組裝過程為例,系統(tǒng)研究了溶劑和離子對納米材料自組裝的影響。為了避免多種化學(xué)物質(zhì)共存帶來的復(fù)雜性,我們采用兩步法來構(gòu)建純凈而簡單的反應(yīng)條件,即首先制備出堿式醋酸鋅納米片作為前驅(qū)物,然后考察其在各種純凈溶劑或鹽溶液中的轉(zhuǎn)變與自組裝過程。我們首先研究了蒸餾水、乙醇、甲醇等三種極性質(zhì)子溶劑和蒸餾水-乙醇混合溶劑的影響,然后研究了 COOH-,NO3-,CO32-,Cl-,SO42-等多種陰離子和陽離子的影響。我們從同一種前驅(qū)物出發(fā),調(diào)控生長出了多種形貌結(jié)構(gòu)的ZnO,包括量子點、納米球、納米片、圓柱、圓錐、棱臺,以及前所未有的三棱柱、四棱柱和五棱柱。這些結(jié)果有力證明了溶劑和離子對納米材料自組裝過程的調(diào)控作用實驗表明,蒸餾水、甲醇、乙醇等質(zhì)子溶劑對堿式醋酸鋅納米片的作用不僅僅是提供一個分散環(huán)境,更重要的是可以促進其分解,并將誘導(dǎo)所生成ZnO的自組裝過程。在該過程中,溶劑的物理化學(xué)性質(zhì)和結(jié)構(gòu)都會起到重要作用。例如,溶劑的極性一方面會影響溶液中溶劑與納米晶之間以及納米晶與納米晶之間的作用力;另一方面會影響溶液中各種離子的溶解度,從而影響各種離子在納米晶表面的吸附過程,并最終影響到納米晶之間的作用力和自組裝。而溶劑的局域結(jié)構(gòu)會影響溶劑中離子的分布,并可作為納米顆粒自組裝的模板。我們發(fā)現(xiàn),離子對納米材料自組裝的影響與它們和納米晶之間的結(jié)合力密切相關(guān):如果離子與納米晶的結(jié)合力較強,那么離子將可能會與納米材料發(fā)生化學(xué)反應(yīng);如果離子與納米晶的結(jié)合力較弱,那么離子也會吸附到納米晶的特定晶面,從而影響納米材料在各晶面上的自組裝。在上述研究過程中,我們調(diào)控生長出了多種形貌結(jié)構(gòu)的ZnO,這些樣品各具特點,具有廣泛的應(yīng)用價值。例如,所制備的ZnO量子點能夠發(fā)射很強的綠光,可以用于生物成像;而所制備的ZnO孿生圓柱和孿生棱臺能夠強烈散射可見光,如果旋涂到太陽能電池的電極板上,則可以有效提高光捕獲能力,從而提高能量轉(zhuǎn)換效率。
[Abstract]:Self-assembly of nanomaterials is one of the hotspots in the field of nanoscience, because self-assembly is not only a growth mechanism of nanomaterials. And it can be used to construct nanostructures with specific collective properties. Self-assembly is a very complex process that is subject to a variety of factors, including the shape of the self-assembled unit, the electric dipole moment, the magnetic dipole moment, the hydrogen bond. All kinds of driving forces such as van der Waals force, as well as the regulation of electric field, magnetic field, light, etc. At present, the study of self-assembly mechanism is still going on in depth. Solvents and ions are two important substances, and there are many interactions with nanocrystals, such as adsorption / desorption, hydrogen bond, hydrostatic power, etc. Therefore, it can be inferred that they will have an important effect on the self-assembly of nanomaterials in solution. In this paper, the conversion and self-assembly process from basic zinc acetate to ZnO is taken as an example. The effects of solvents and ions on the self-assembly of nanomaterials were systematically studied. In order to avoid the complexity caused by the coexistence of various chemical substances, we used a two-step method to construct pure and simple reaction conditions. That is to say, the basic zinc acetate nanoparticles were prepared as precursors, and then their transformation and self-assembly in various pure solvents or salt solutions were investigated. The effects of three polar proton solvents such as methanol and distilled water-ethanol mixed solvents on the effects of various anions and cations such as COOH-no _ 3-CO _ (32) O _ (2) O _ (2) O _ (2) O _ (2) O _ (2) and CO _ (32) O _ (2) O _ (2) O _ (2) were studied. Zno has grown in a variety of morphologies, including quantum dots, nanospheres, nanochips, cylinders, cones, prisms, and unprecedented triangular prisms. Four prism and five prism. These results strongly demonstrate the effects of solvents and ions on the self-assembly process of nanomaterials. Experiments show that distilled water, methanol, The effect of proton solvents, such as ethanol, on basic zinc acetate nanoparticles is not only to provide a dispersed environment, but also to promote its decomposition and induce the self-assembly process of the resulting ZnO. The physical and chemical properties and structure of the solvent play an important role. For example, the polarity of the solvent will affect the force between the solvent and the nanocrystalline and between the nanocrystalline and the nanocrystalline. On the other hand, it will affect the solubility of the ions in the solution, thus affecting the adsorption process of the ions on the nanocrystalline surface. The local structure of the solvent will affect the distribution of ions in the solvent and can be used as a template for the self-assembly of nanoparticles. The effect of ions on the self-assembly of nanomaterials is closely related to the adhesion between them and nanocrystals: if the binding force between ions and nanocrystals is strong, then ions may react with nanomaterials; If the binding force between ions and nanocrystals is weak, then ions will also adsorb to the specific crystal planes of nanocrystals, which will affect the self-assembly of nanomaterials on each crystal plane. We have controlled and grown a variety of ZnO with different morphology and structure. These samples have their own characteristics and have wide application value. For example, the ZnO quantum dots can emit strong green light and can be used in biological imaging. The ZnO twin cylinder and the twin prism can scatter the visible light strongly. If the solar cell is rotated on the electrode plate, the optical capture ability can be improved effectively and the energy conversion efficiency can be improved.
【學(xué)位授予單位】：南京大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2017
【分類號】：O614.241;TB383.1
，

本文編號：1650666