囊泡串:一种不寻常类型的水凝中的流动行为
Fredric M Menger1, Andrey V Peresypkin
1Department of Chemistry, Emory University, 1515 Pierce Drive, Atlanta, Georgia 30322, USA. menger@emory.edu
Journal of the American Chemical Society
|May 2, 2003
概括
十种不对称的双子表面活性剂自组装成凝聚性囊泡,形成凝,使水变硬. 凝在机械上是可逆的,对表面活性剂结构敏感,具有潜在的应用.
科学领域:
- 超分子化学 超分子化学
- 材料科学 材料科学 材料科学
背景情况:
- 不对称的双子座表面活性剂自组装成复杂的结构.
- 囊泡形成和随后的凝是表面活性剂化学中的关键现象.
研究的目的:
- 研究不对称的双子表面活性剂在囊泡和凝中的自我组装.
- 了解影响囊泡凝聚力和凝形成的因素.
- 探索产生的凝的机械性能和可逆性.
主要方法:
- 动态光散射 (DLS) 用于囊泡大小分析.
- 传输电子显微镜 (TEM) 和低温高分辨率扫描电子显微镜 (cryo-HRSEM) 用于形态学研究.
- 风病学实验以评估凝特性和机械可逆性.
主要成果:
- 不对称的双子表面活性剂在稀释水溶液中自组合成囊泡.
- 囊泡形成凝聚在一起的"串上的珍珠"结构,导致凝结.
- 一种特定的Gemini表面活性剂未能形成凝,而是组装成块块.
- 在表面活性剂的化温度 (T) 以上,凝是机械可逆的.
- 凝强度高度依赖于双子星表面活性剂的分子结构.
结论:
- 从囊泡表面突出的短链驱动凝聚力和凝形成.
- 自组装路径 (链条与块) 决定了凝能力.
- 研究的双子表面活性剂,囊泡和凝具有各种实际应用的潜力.
相关概念视频
Cohesion
Cohesion is the attraction between molecules of the same type, such as water molecules. Water molecules have an overall neutral charge but are polar molecule. An oxygen atom in one water molecule has a partial negative charge that can bind to a hydrogen atom with a partial positive charge in a second water molecule, forming a hydrogen bond. Each water molecule can form up to four hydrogen bonds with other water molecules. Hydrogen bonds are responsible for water's cohesive nature.
On a surface,...
On a surface,...
Colloids and Suspensions
Children at play often make suspensions such as mixtures of mud and water, flour and water, or a suspension of solid pigments in water known as tempera paint. These suspensions are heterogeneous mixtures composed of relatively large particles visible to the naked eye or seen with a magnifying glass. They are cloudy, and the suspended particles settle out after mixing. The suspended particles in a suspension settle out after some time of mixing. The separation of particles from a suspension is...
Characteristics of Fluids
When a force is applied parallel to the top surface of a solid, it resists the applied force due to the internal frictional forces between the layers of the solid known as shearing resistance. However, when the force is removed, the shearing forces restore the original shape of the solid. Other deformation forces also cause temporary changes in shape if the forces are not beyond a threshold magnitude. Solids tend to retain their shape, making the study of their rest and motion easier. Beyond...
Rise of Liquid in a Capillary Tube
When very thin cylindrical tubes, called capillaries, are dipped in a liquid, the liquid rises or falls in the tube compared to the surrounding liquid. This phenomenon is called capillary action. Capillary action occurs due to the combination of two opposing forces: the cohesive forces of the liquid, which cause it to stick to itself and form a rounded shape, and the adhesive forces between the liquid and the walls of the container, which cause the liquid to be attracted to the container walls.
Characteristics of Fluids
Fluids differ from solids primarily in their molecular structure and stress response. Solids have tightly packed molecules with strong intermolecular forces, maintaining their shape and resisting deformation. In contrast, fluids have molecules spaced farther apart with weaker forces, allowing them to flow and deform easily.
Fluids, which include both liquids and gases, are substances that deform continuously under shearing stress. For example, water and oil are liquids with molecules that can...
Fluids, which include both liquids and gases, are substances that deform continuously under shearing stress. For example, water and oil are liquids with molecules that can...
Surface Tension of Fluid
Surface tension is a fundamental property of fluids, occurring at the boundary between a liquid and a gas or between two immiscible liquids. This phenomenon arises from the cohesive forces between molecules at the fluid's surface, creating an effect similar to a stretched elastic membrane. Inside each fluid, molecules are equally attracted in all directions by neighboring molecules, but surface molecules experience a net inward force, resulting in surface tension.
Surface tension varies with...
Surface tension varies with...


