高相互作用混合物PCHMA/dPS的热力学 由TOF-SANS
William N Sharratt1, Yutaka Aoki1, Sebastian Pont1
1Department of Chemical Engineering, Imperial College London, London SW7 2AZ, U.K.
Macromolecules
|July 31, 2023
概括
我们使用小角度中子散射 (SANS) 研究了聚环基甲酸盐/脱聚乙烯 (PCHMA/dPS) 混合物的热力学. 这种高度相互作用的混合物显示出混合的自由能量对温度的严重依赖.
科学领域:
- 聚合物科学 聚合物科学
- 材料科学 是一种材料科学.
- 热力学是一种热力学.
背景情况:
- 研究聚合物混合物热力学对于材料设计至关重要.
- 聚合物混合物在其相位边界附近存在由于降解的实验挑战.
- 聚环基甲酸/脱聚乙烯 (PCHMA/dPS) 是一个具有挑战性的混合系统.
研究的目的:
- 为了研究高度相互作用的PCHMA/dPS混合物的热力学.
- 为了确定混合和相互作用参数的自由能量.
- 为了确定随机相近似 (RPA) 对T跳跃实验的适用性.
主要方法:
- 小角度中子散射 (SANS) 在飞行时间 (TOF) 模式下.
- 辅助技术:显微镜,热量计和热重量计分析.
- 在单相区域内的温度 (T) 跳跃实验.
主要成果:
- 同热 SANS 数据符合 RPA,产生 G′′, χ̅ 和旋点温度.
- 远离玻璃过渡温度的T跳实验被RPA描述得很好.
- 在T跳跃过程中,TOF-SANS精确地解析了G′′(T) 和 χ̅(T),显示出一个的依赖关系:G′′(T) = -0.00228 + 1.1821/T [K].
结论:
- PCHMA/dPS是一种高度相互作用的,部分可混合的混合物.
- 在这个系统中,RPA为T跳实验提供了接近平衡的结果.
- 与其他较低临界溶液温度 (LCST) 混合物进行了基准测试.
相关概念视频
Path Between Thermodynamics States
3.2K
Consider the two thermodynamic processes involving an ideal gas that are represented by paths AC and ABC in Figure 1:
3.2K
Maxwell's Thermodynamic Relations
2.8K
Maxwell's thermodynamic relations are very useful in solving problems in thermodynamics. Each of Maxwell's relations relates a partial differential between quantities that can be hard to measure experimentally to a partial differential between quantities that can be easily measured. These relations are a set of equations derivable from the symmetry of the second derivatives and the thermodynamic potentials.
All thermodynamic potentials are exact differentials. Therefore, their second-order...
All thermodynamic potentials are exact differentials. Therefore, their second-order...
2.8K
Thermodynamic Potentials
879
Thermodynamic potentials are state functions that are extremely useful in analyzing a thermodynamic system. They have dimensions of energy. The four important thermodynamic potentials are internal energy, enthalpy, Helmholtz free energy, and Gibbs free energy. These thermodynamic potentials can be expressed using two of the following variables: pressure, volume, temperature, and entropy. These two variables are expressed as the rate of change of the thermodynamic potential with respect to other...
879
Thermal Sigmatropic Reactions: Overview
2.1K
Sigmatropic rearrangements are a class of pericyclic reactions in which a σ bond migrates from one part of a π system to another. These are intramolecular rearrangements where the total number of σ and π bonds remain unchanged.
Sigmatropic shifts are classified based on an order term [i, j ], where i and j indicate the number of atoms across which each end of the σ bond migrates. Below are examples of a [3,3] sigmatropic shift in...
Sigmatropic shifts are classified based on an order term [i, j ], where i and j indicate the number of atoms across which each end of the σ bond migrates. Below are examples of a [3,3] sigmatropic shift in...
2.1K
Thermodynamic Systems
5.2K
A thermodynamic system is a set of objects whose thermodynamic properties are of interest. The system is considered to be embedded in its surroundings or the environment. The system and its environment can exchange heat and do work on each other through a boundary that separates them. However, the immediate surroundings of the system interact with it directly and therefore have a much stronger influence on its behavior and properties.
Consider an example of tea boiling in a kettle. The...
Consider an example of tea boiling in a kettle. The...
5.2K
Thermodynamics: Activity Coefficient
1.5K
Activity is the measure of the effective concentration of the species in solution. It can be expressed as the product of the molar concentration of the species and its activity coefficient. The activity coefficient is a dimensionless quantity and depends on the total ionic strength of the solution.
The activity coefficient is a measure of the deviation from ideal behavior. When the ionic strength of the solution is minimal, the activity coefficient of an ionic species is close to unity, making...
The activity coefficient is a measure of the deviation from ideal behavior. When the ionic strength of the solution is minimal, the activity coefficient of an ionic species is close to unity, making...
1.5K


