聚合物溶液中的扩散蒸发动力学是无处不在的.
Max Huisman1, Wilson C K Poon1, Patrick B Warren1,2
1SUPA and School of Physics and Astronomy, The University of Edinburgh, Peter Guthrie Tait Road, Edinburgh EH9 3FD, UK. davide.marenduzzo@ed.ac.uk.
Soft matter
|January 29, 2025
概括
一项新的研究显示,溶剂-空气接口的聚合物层会导致扩散有限蒸发 (DLE),这是一个强大的系统,蒸发速度随时间变化为t^-1/2,独立于湿度.
科学领域:
- 聚合物物理 聚合物物理
- 接口科学 接口科学
- 流体动力学 流体动力学
背景情况:
- 在接口处的高度聚合物层可以改变溶剂蒸发.
- 以前的理论和实验表明,蒸发速度的特定时间缩放.
研究的目的:
- 研究从聚合物涂层接口中溶剂蒸发的动力学.
- 确认和扩大对扩散有限蒸发 (DLE) 系统的理解.
- 探索DLE的参数空间和维度.
主要方法:
- 使用相场建模来模拟溶剂蒸发.
- 分析聚合物-溶剂系统的动态状态图.
- 发展观察到的缩放规律的理论论证.
主要成果:
- 识别了扩散有限蒸发 (DLE) 作为一个强大的,自然出现的系统.
- 证明了DLE蒸发速率随着时间的推移而变化为-1/2 (t^-1/2).
- 显示的DLE对环境湿度不敏感,并且主导着系统的动态.
结论:
- 阶段场建模证实了DLE作为一个关键的蒸发模式.
- 在各种参数中,t^-1/2缩放定律是广泛适用的.
- DLE也可能发生在二维系统中,这需要进一步调查.
相关概念视频
Theories of Dissolution: Diffusion Layer Model
672
Dissolution, the process by which drug particles dissolve in a solvent, is explained by the diffusion layer model, a theoretical framework that simulates the absorption of oral drugs and allows us to analyze experimental data.
This process starts with a thin layer, saturated with the drug, forming at the interface between the solid and liquid. The solute then diffuses from this layer into the main solution. The Noyes-Whitney equation suggests that the rate of dissolution relies on the diffusion...
This process starts with a thin layer, saturated with the drug, forming at the interface between the solid and liquid. The solute then diffuses from this layer into the main solution. The Noyes-Whitney equation suggests that the rate of dissolution relies on the diffusion...
672
Theories of Dissolution: The Danckwerts' Model and Interfacial Barrier Model
267
Various dissolution theories provide insight into the factors that influence the dissolution rate. Danckwerts' Model suggests that turbulence, rather than a stagnant layer, characterizes the dissolution medium at the solid-liquid interface. In this model, the agitated solvent contains macroscopic packets that move to the interface via eddy currents, facilitating the absorption and delivery of the drug to the bulk solution. The regular replenishment of solvent packets maintains the...
267
Step-Growth Polymerization: Overview
3.4K
Step-growth or condensation polymerization is a stepwise reaction of bi or multifunctional monomers to form long-chain polymers. As all the monomers are reactive, most of the monomers are consumed at the early stages of the reaction to form small chains of reactive oligomers, which then combine to form long polymer chains in the late stages. Hence, the reaction has to proceed for a long time to achieve high molecular weight polymers.
Many natural and synthetic polymers are produced by...
Many natural and synthetic polymers are produced by...
3.4K
Molecular Weight of Step-Growth Polymers
2.1K
Step growth polymerization involves bi or multifunctional monomers. Bifunctional monomers react to form linear step growth polymers, whereas multifunctional monomers react to form non-linear or branched polymers.
As the step-growth polymerization involves step-wise condensation of monomers, the molecular weight also builds up eventually. Consequently, high molecular weight polymers are obtained at the late stages of the polymerization, where 99% of monomers have been consumed.
The extent of the...
As the step-growth polymerization involves step-wise condensation of monomers, the molecular weight also builds up eventually. Consequently, high molecular weight polymers are obtained at the late stages of the polymerization, where 99% of monomers have been consumed.
The extent of the...
2.1K
Vapor Pressure Lowering
26.0K
The equilibrium vapor pressure of a liquid is the pressure exerted by its gaseous phase when vaporization and condensation are occurring at equal rates:
Dissolving a nonvolatile substance in volatile liquid results in a lowering of the liquid’s vapor pressure. This phenomenon can be explained by considering the effect of added solute molecules on the liquid's vaporization and condensation processes. To vaporize, solvent molecules must be present at the surface of the solution....
Dissolving a nonvolatile substance in volatile liquid results in a lowering of the liquid’s vapor pressure. This phenomenon can be explained by considering the effect of added solute molecules on the liquid's vaporization and condensation processes. To vaporize, solvent molecules must be present at the surface of the solution....
26.0K
Polymers: Molecular Weight Distribution
3.2K
For any given polymer, the weight average molecular weight (Mw) is higher than, if not equal to, the number average molecular weight (Mn). The only situation in which the weight average molecular weight and the number average molecular weight are equal is when a polymer consists only of chains with equal molecular weight. However, this never happens in a synthetic polymer, since it is difficult to control the polymerization process up to a molecular level with accuracy to a hundred percent.
3.2K


