在充电的合体二氧化分散中,单向晶体生长是由基底扩散驱动的
Junpei Yamanaka1, Masako Murai, Yumie Iwayama
1Faculty of Pharmaceutical Sciences, Nagoya City University, 3-1 Tanabe, Mizuho, Nagoya, Aichi 467-8603, Japan. yamanaka@phar.nagoya-cu.ac.jp
Journal of the American Chemical Society
|June 10, 2004
概括
充电的合体二氧化颗粒显示出一种新的单向晶体生长. 这一由二烯扩散和粒子充电驱动的过程,产生了厘米尺度的柱状晶粒.
科学领域:
- 材料科学 材料科学 材料科学
- 合体化学 合体化学
- 晶体学 晶体学是指结晶学.
背景情况:
- 在材料科学中,体分散是基本的.
- 控制合体系统中的晶体生长对于先进的材料制造至关重要.
- 纳米粒子由于其可调节的特性而被广泛使用.
研究的目的:
- 研究一种新的方法,用于在充电的合体二氧化分散物中单向晶体生长.
- 阐明控制观察到的晶体形成的机制.
- 探索制造厘米尺度的合晶体的潜力.
主要方法:
- 使用带电的合体二氧化颗粒的水性分散物.
- 引入皮里丁,一个弱基,以诱导扩散和中和反应.
- 使用显微镜和表征技术观察和分析由此产生的晶体生长.
主要成果:
- 实现了合体二氧化的新型单向晶体生长.
- 形成柱状的水晶粒,尺寸为厘米和亚厘米.
- 证明增长是由二胺扩散,表面中和,粒子充电和电荷诱导结晶驱动的.
结论:
- 皮里丁诱导的扩散和随后的充电促进了可控的,单向的晶体生长,在二氧化分散.
- 这些发现为合成大规模的合晶体提供了新的途径.
- 这种方法对开发新型功能材料有影响.
相关概念视频
Formation of Complex Ions
A type of Lewis acid-base chemistry involves the formation of a complex ion (or a coordination complex) comprising a central atom, typically a transition metal cation, surrounded by ions or molecules called ligands. These ligands can be neutral molecules like H2O or NH3, or ions such as CN− or OH−. Often, the ligands act as Lewis bases, donating a pair of electrons to the central atom. These types of Lewis acid-base reactions are examples of a broad subdiscipline called coordination...
Crystal Growth: Principles of Crystallization
Crystallization is a phase transformation process in which crystals are precipitated from a supersaturated solution or formed from other sources. During crystallization, atoms or molecules arrange themselves into a well-defined, rigid crystal lattice to minimize energy.
Initiating crystallization involves manipulating the concentration of the solute and the temperature of the solution. Since crystal growth occurs when the ratio of concentration and solubility of the solute in the solvent – the...
Initiating crystallization involves manipulating the concentration of the solute and the temperature of the solution. Since crystal growth occurs when the ratio of concentration and solubility of the solute in the solvent – the...
Cationic Chain-Growth Polymerization: Mechanism
The cationic polymerization mechanism consists of three steps: initiation, propagation, and termination. In the initiation step of the polymerization process, the π bond of a monomer gets protonated by the Lewis acid catalyst, which is formed from boron trifluoride and water. The protonation of the π bond generates a carbocation stabilized by the electron‐donating group. In the propagation step, the π bond of the second monomer acts as a nucleophile and attacks the generated carbocation,...
Carrier Generation and Recombination
Carrier generation is the process by which electron-hole pairs (EHPs) are created within the semiconductor. In direct-bandgap semiconductors, such as gallium arsenide (GaAs), this occurs efficiently when energy absorption prompts valence electrons to leap into the conduction band, leaving behind holes.
This process is given by the generation rate G and is efficient due to the conservation of momentum between the valence band maximum and conduction band minimum.
Indirect generation involves an...
This process is given by the generation rate G and is efficient due to the conservation of momentum between the valence band maximum and conduction band minimum.
Indirect generation involves an...
P-N junction
A p-n junction is formed when p-type and n-type semiconductor materials are joined together. At the interface of the p-n junction, holes from the p-side and electrons from the n-side begin to diffuse into the opposite sides due to the concentration gradient. This diffusion of carriers leads to a region around the junction where there are no free charge carriers, known as the depletion region. The charge density within the depletion region for the n-side and p-side can be described by the...
The Electrical Double Layer
In the region where two bulk phases meet, an intricate electric charge distribution arises due to charge transfer, ion adsorption, molecular orientation, and charge distortion. This complex distribution is commonly referred to as the electrical double layer.When a solid electrode interfaces with ions in an electrolyte solution, the speed of electron transfer dictates the rates of oxidation and reduction. The electrode acquires a charge through the escape of atoms into the solution as cations or...


