在聚合物纳米复合材料中触发位移分布的高斯式到指数式转变通过吸附诱导的捕获
Ming Hu1,2, Hongbo Chen1, Hongru Wang1,2
1State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, Jilin 130022, People's Republic of China.
ACS nano
|October 25, 2023
概括
研究人员控制了无序系统中的粒子扩散,通过调整纳米粒子度和相互作用,从高斯式转变为指数式行为. 这一发现对于理解软和纳米材料至关重要.
科学领域:
- 软物质物理学 软物质物理学
- 材料科学 材料科学 材料科学
- 统计力学 统计力学
背景情况:
- 无序的系统经常表现出异常扩散,其特点是指数位移分布,而不是典型的布朗运动的高斯统计数据.
- 在受混乱强度影响的粒子扩散中,对这种高斯式到指数式过渡的实验控制仍然是一个重大挑战.
研究的目的:
- 实验性地研究和控制从高斯式到指数位移分布在粒子扩散中的过渡.
- 确定控制纳米粒子-聚合物混合物这种转变的关键参数.
主要方法:
- 在有吸引力的纳米粒子-聚合物混合物中利用聚乙烯糖醇 (PEG) 的扩散.
- 控制了纳米粒子的体积分数和相互作用,以调整障碍的强度.
- 采用蒙特卡洛模拟,使用微观模型通过可逆吸附捕获聚合物.
主要成果:
- 确定了纳米粒子度和相互作用作为关键的"旋",以可控地改变位移分布的形状.
- 在位移分布中观察到从高斯式到指数尾的明显过渡.
- 实验结果与从连续时间随机步行修改的大偏差方法的理论预测保持一致.
结论:
- 在无序的软材料中,证明了对高斯式到指数式扩散过渡的实验控制.
- 这项研究阐明了控制移位分布的指数式衰变的基本物理,这在软和纳米材料中很常见.
- 为理解和操纵复杂流体系统中的异常扩散提供了一个框架.
相关概念视频
Molecular Weight of Step-Growth Polymers
2.2K
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...
2.2K
Ziegler–Natta Chain-Growth Polymerization: Overview
3.3K
Ziegler–Natta polymerization is another form of addition or chain‐growth polymerization used for synthesizing linear polymers over branched polymers. The catalyst used for polymerization is the Ziegler–Natta catalyst, named after Karl Ziegler and Giulio Natta, who developed it in 1953. This catalyst is an organometallic complex of titanium tetrachloride and triethyl aluminum, with the active form of the catalyst being an alkyl titanium compound. Using the Ziegler–Natta...
3.3K
Step-Growth Polymerization: Overview
3.5K
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...
3.5K
Polymers: Molecular Weight Distribution
3.4K
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.
3.4K
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
Polymer Classification: Crystallinity
2.9K
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...
2.9K


