哈尔巴赫阵列诱导磁场对齐在化纳米复合材料中的化
Viney Ghai1, Ases Akas Mishra1, Enling Huang2
1Department of Industrial and Materials Science, Chalmers University of Technology, Göteborg, 41296, Sweden.
Advanced science (Weinheim, Baden-Wurttemberg, Germany)
|December 24, 2024
概括
对齐的六角化 (hBN) 纳米片显著提高聚合物复合材料的导热性. 这种新的磁对齐方法提高了先进应用的热管理和电绝缘.
科学领域:
- 材料科学 材料科学 材料科学
- 聚合物科学 聚合物科学
- 纳米技术 纳米技术
背景情况:
- 提高聚合物的导热性对于先进的技术应用至关重要.
- 聚甲基 (PDMS) 复合材料需要改进的热管理解决方案.
- 六角性化 (hBN) 纳米板具有提高导热性的潜力.
研究的目的:
- 开发一种用于在PDMS矩阵中对准hBN纳米片的新方法.
- 研究对齐的hBN纳米板对PDMS复合材料的热和介电性能的影响.
- 探索这些复合材料在储能应用中的潜力.
主要方法:
- 利用哈尔巴赫阵列来生成一个统一的磁场,用于hBN纳米板对齐.
- 将hBN纳米片纳入PDMS矩阵,并以不同度 (例如10 wt.%) 进行嵌入.
- 采用旋转磁场来实现hBN纳米片的垂直对齐.
主要成果:
- 实现了3.58 W mK-1的热导率,其中10 wt.%的垂直对齐的hBN纳米板,比纯 PDMS 增加了1950%.
- 通过面向的hBN纳米片证明了更好的电绝缘性能.
- 观察到垂直导向样本的介电常数 (≈14) 的增加和低介电损失 (100 Hz 的 0.0049) .
结论:
- 磁对齐的hBN纳米板是一种有效的策略,可以显著提高PDMS复合材料的导热性.
- 定向的hBN纳米板改善介电性质,使复合材料适用于储能电容器.
- 这种方法为开发具有定制热和电功能的先进聚合物复合材料提供了有前途的途径.
相关概念视频
π Electron Effects on Chemical Shift: Overview
1.0K
An applied magnetic field causes loosely bound π-electrons in organic molecules to circulate, producing a local or induced diamagnetic field over a large spatial volume. As the molecules tumble in solution, the field generated by π-electrons in spherical substituents results in a zero net field. However, the net field generated by π-electrons in non-spherical substituents is not zero. The effect of this induced field depends on the orientation of the molecule with respect to B0,...
1.0K
Atomic Nuclei: Nuclear Magnetic Moment
1.0K
All atomic nuclei are positively charged. When they have a nonzero spin, they behave like rotating charges. As a consequence of their charge and spin, these nuclei generate a magnetic field (B). This, in turn, gives rise to a magnetic moment (μ), which is randomly oriented in the absence of an external magnetic field. When an external magnetic field (B0) is applied, the magnetic moment vectors can align with the field or against it in 2 + 1 orientations. A hydrogen nucleus, which is just a...
1.0K
Diamagnetic Shielding of Nuclei: Local Diamagnetic Current
831
An applied magnetic field causes the electrons present in the molecule to circulate, setting up a local diamagnetic current within the molecule. The local diamagnetic current arising from circulating sigma-bonding electrons induces a magnetic field, Blocal that opposes the applied magnetic field, B0. The effective magnetic field experienced by these nuclei is given by the difference between the applied and local magnetic fields in a phenomenon called local diamagnetic shielding. Essentially,...
831
Hybridization of Atomic Orbitals I
46.5K
The mathematical expression known as the wave function, ψ, contains information about each orbital and the wavelike properties of electrons in an isolated atom. When atoms are bound together in a molecule, the wave functions combine to produce new mathematical descriptions that have different shapes. This process of combining the wave functions for atomic orbitals is called hybridization and is mathematically accomplished by the linear combination of atomic orbitals. The new orbitals that...
46.5K
Atomic Nuclei: Magnetic Resonance
624
The number of nuclear spins aligned in the lower energy state is slightly greater than those in the higher energy state. In the presence of an external magnetic field, as the spins precess at the Larmor frequency, the excess population results in a net magnetization oriented along the z axis. When a pulse or a short burst of radio waves at the Larmor frequency is applied along the x axis, the coupling of frequencies causes resonance and flips the nuclear spins of the excess population from the...
624
Valence Bond Theory
8.5K
Coordination compounds and complexes exhibit different colors, geometries, and magnetic behavior, depending on the metal atom/ion and ligands from which they are composed. In an attempt to explain the bonding and structure of coordination complexes, Linus Pauling proposed the valence bond theory, or VBT, using the concepts of hybridization and the overlapping of the atomic orbitals. According to VBT, the central metal atom or ion (Lewis acid) hybridizes to provide empty orbitals of suitable...
8.5K


