从离子集群动态到离子聚合物溶液中的网络约束
Sidath Wijesinghe1,2, Chathurika Kosgallana1, Manjula Senanayake1
1Department of Chemistry, Clemson University, Clemson, South Carolina 29634, USA.
Physical review. E
|April 18, 2024
概括
离子聚合物网络在多个尺度上表现出合动态. 改变离子集群的静电环境使其稳定,影响聚合物链运动和宏观网络行为.
科学领域:
- 聚合物科学 聚合物科学
- 材料科学 材料科学 材料科学
- 软物质物理学 软物质物理学
背景情况:
- 电离性聚合物的物理网络利用离子集群作为交叉链接.
- 这些网络的宏观性质是由从离子集群到聚合物链运动的动力学决定的.
研究的目的:
- 在聚乙烯硫酸盐网络中跨长度尺度直接关联合动力学.
- 调查物理交叉连接的静电环境的改变如何影响网络动态.
主要方法:
- 将中子旋转回声 (NSE) 测量与分子动力学 (MD) 模拟相结合.
- 研究多二硫酸网络的多二硫酸.
- 通过温度升高和静电环境的改变扰乱网络.
主要成果:
- 实验动态结构因子与MD模拟显示出极好的一致性.
- 托卢烯中的离子集群在广泛的温度范围内在数百纳秒内保持稳定.
- 修改溶剂的介电常数 (通过添加乙醇) 改变了集群大小,但保持了稳定性,增强了聚合物链动态.
结论:
- 该研究为电离性聚合物网络的动态提供了多层次的洞察力.
- 离子集群作为稳定的物理交叉链接,影响整体网络动态.
- 静电环境是控制这些聚合物网络的稳定性和动态性的关键因素.
相关概念视频
Polymer Classification: Crystallinity
2.8K
Unlike ionic or small covalent molecules, polymers do not form crystalline solids due to the diffusion limitations of their long-chain structures. However, polymers contain microscopic crystalline domains separated by amorphous domains.
Crystalline domains are the regions where polymer chains are aligned in an orderly manner and held together in proximity by intermolecular forces. For example, chains in the crystalline domains of polyethylene and nylon are bound together by van der Waals...
Crystalline domains are the regions where polymer chains are aligned in an orderly manner and held together in proximity by intermolecular forces. For example, chains in the crystalline domains of polyethylene and nylon are bound together by van der Waals...
2.8K
Anionic Chain-Growth Polymerization: Mechanism
2.0K
The mechanism for anionic chain-growth polymerization involves initiation, propagation, and termination steps. In the initiation step, a nucleophilic anion, such as butyl lithium, initiates the polymerization process by attacking the π bond of the vinylic monomer. As a result, a carbanion, stabilized by the electron‐withdrawing group, is generated. The resulting carbanion acts as a Michael donor in the propagation step and attacks the second vinylic monomer, which acts as a Michael...
2.0K
Ion Exchange
591
Ion exchange chromatography separates charged molecules from a solution by reversibly exchanging them with mobile, or 'active', ions associated with the oppositely charged stationary phase. This method can be used to separate ions, soften and deionize water, and purify solutions. The polymers comprising the ion-exchange column are high-molecular-weight and chemically stable polymers, crosslinked to be porous and essentially insoluble. They are also functionalized with either acidic or...
591
Cationic Chain-Growth Polymerization: Mechanism
2.3K
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...
2.3K
Intermolecular Forces
58.2K
Atoms and molecules interact through bonds (or forces): intramolecular and intermolecular. The forces are electrostatic as they arise from interactions (attractive or repulsive) between charged species (permanent, partial, or temporary charges) and exist with varying strengths between ions, polar, nonpolar, and neutral molecules. The different types of intermolecular forces are ion–dipole, dipole–dipole, hydrogen bonds, and dispersion; among these, dipole–dipole, hydrogen...
58.2K
Anionic Chain-Growth Polymerization: Overview
2.1K
The polymerization process that involves carbanion as an intermediate is called anionic polymerization. It is also a type of addition or chain-growth polymerization. Anionic polymerization gets initiated by a strong nucleophile such as an organolithium or a Grignard reagent. The most commonly used initiator for anionic polymerization is butyl lithium. Monomers involved in anionic polymerization must possess a vinyl group bonded to one or two electron-withdrawing groups. For instance,...
2.1K


