合体硬球晶体的生长受到大型球形杂质的阻碍
Volkert W A de Villeneuve1, Roel P A Dullens, Dirk G A L Aarts
1Van't Hoff Laboratory, Debye Research Institute, University of Utrecht, Padualaan 8, 3584 CH Utrecht, Netherlands.
概括
大量的杂质会破坏合体晶体的生长. 较小的杂质会导致由于局部晶体丧而导致更大的生长抑制,影响晶体结构和形成.
科学领域:
- 体科学是关于体的科学.
- 材料科学是一种材料科学.
- 结晶化 结晶化 结晶化
背景情况:
- 杂质显著影响晶体核形成,生长和最终结构.
- 了解杂质的影响对于控制结晶过程至关重要.
研究的目的:
- 调查大型球形聚甲基甲酸盐 (PMMA) 杂质对PMMA合物晶体生长的影响.
- 分析杂质大小如何影响晶体生长动态和结构.
主要方法:
- 在密度和光学匹配的无极溶剂中使用单分散,硬的PMMA合物.
- 采用激光扫描共聚焦显微镜,对杂质周围的晶体生长的二维切片进行成像.
- 观察到的晶体生长始于样品底部.
主要成果:
- 杂质作为谷物边界的中心,周围有一个持久的液体粒子层.
- 晶体生长速度对杂质的大小高度敏感.
- 较小的杂质表现出更明显的晶体生长抑制,表明本地晶体丧.
结论:
- 杂质的曲率,特别是较小的杂质,会引起局部晶体的挫折,显著影响着合晶体的生长.
- 杂质大小是控制晶体生长抑制和结构缺陷程度的关键参数.
相关概念视频
Ionic Crystal Structures
Ionic crystals consist of two or more different kinds of ions that usually have different sizes. The packing of these ions into a crystal structure is more complex than the packing of metal atoms that are the same size.
Most monatomic ions behave as charged spheres, and their attraction for ions of opposite charge is the same in every direction. Consequently, stable structures for ionic compounds result (1) when ions of one charge are surrounded by as many ions as possible of the opposite...
Most monatomic ions behave as charged spheres, and their attraction for ions of opposite charge is the same in every direction. Consequently, stable structures for ionic compounds result (1) when ions of one charge are surrounded by as many ions as possible of the opposite...
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...
X-ray Diffraction of Biological Samples
X-ray diffraction or XRD is an analytical tool that utilizes X-rays to study ordered structures such as crystalline organic and inorganic samples, polycrystalline materials, proteins, carbohydrates, and drugs.
According to Bragg's law, when X-rays strike the sample positioned on a stage, the rays are scattered by the electron clouds around the sample atoms. The X-ray diffraction or scattering is caused by constructive interference of the X-ray waves that reflect off the internal crystal...
According to Bragg's law, when X-rays strike the sample positioned on a stage, the rays are scattered by the electron clouds around the sample atoms. The X-ray diffraction or scattering is caused by constructive interference of the X-ray waves that reflect off the internal crystal...
Imperfections in Crystal Structure: Point, Line and Plane Defects
A perfect crystal, in theory, has a uniform structure with the same unit cell and lattice points throughout. However, any deviation from this periodic arrangement is known as an imperfection or defect. These defects can be categorized into three types: point, line, and plane defects.Point defects occur when there is a deviation from the ideal due to missing atoms, displaced atoms, or additional atoms. These imperfections might occur due to imperfect packing during crystallization or because of...
Imperfections in Crystal Structure: Stoichiometric Point Defects
Schottky defects arise when some lattice points in a crystal, such as those in NaCl, remain unoccupied, creating lattice vacancies without disturbing the overall electrical neutrality of the crystal. This defect is common in ionic crystals where the positive and negative ions are similar in size, as seen in sodium chloride and cesium chloride. The presence of Schottky defects enables the crystal to conduct electricity to a small extent through an ionic mechanism. Electric fields cause nearby...
Imperfections in Crystal Structure: Non-Stoichiometric Defects
Non-stoichiometric defects refer to a type of defect in the crystal structure of a compound where the ratio of its constituent elements deviates from the ideal stoichiometric ratio. There are two main types of non-stoichiometric defects: metal excess defects and metal deficiency defects.Metal excess defects occur when there is a slight surplus of metal ions than what is required by the stoichiometric ratio of the compound. For example, heating a sodium chloride crystal in sodium vapor results...


