相关实验视频
Updated: Jun 1, 2025

11:15
Nanosponge Tunability in Size and Crosslinking Density
Published on: August 4, 2017
7.6K
边界和交叉连接密度调节多域内马特性弹性体的域大小
Takuya Ohzono1, Kaoru Katoh2, Nariya Uchida3
1Research Institute for Electronics and Photonics, National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Higashi, Tsukuba 305-8565, Japan. ohzono-takuya@aist.go.jp.
Soft matter
|January 21, 2025
概括
边界效应和交叉连接密度会影响阴性液晶弹性体 (LCE) 中的多域模式. 固体墙壁减少域大小,而自由表面增加它,提供对LCE属性的控制.
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
- 软物质物理学 软物质物理学
背景情况:
- 阴性液晶弹性体 (LCEs) 在从同位素到阴性阶段灭时表现出多域模式.
- 这些以自我组织的微域为特征的模式,对于光学和机械学的潜在应用至关重要.
- 这些域的形成和相关长度受到液晶秩序和网络不均性的影响.
研究的目的:
- 调查边界条件 (固体墙面与开放表面) 和交叉链接密度如何影响阴性LCE中的多域模式.
- 通过实验可访问的参数来理解域大小和方向相关长度的调制.
- 建立一种实验方法来控制LCE中的多域模式.
主要方法:
- 使用共聚焦极化光显微镜观察和分析多域模式.
- 在LCE中系统变化的交联密度.
- 检查被固体玻璃边界所限制的LCE和具有自由表面的LCE.
主要成果:
- 与LCE相邻的固体墙边界减少了接口附近的域大小.
- 一个开放的表面 (自由边界) 导致域大小增加.
- 更高的交叉链接密度导致更小的域大小和放大边界效应.
结论:
- 观察到的域大小调制归因于聚合物网络有效失调强度的变化,受交联密度和边界约束的影响.
- 这项研究提供了第一个实验性演示,证明了在阴性LCE中对多域模式的全球和本地控制.
- 这些发现为通过操纵网络结构和边界来为设备应用量身定制LCE属性提供了一条途径.
相关概念视频
Polymer Classification: Architecture
2.6K
Polymers are classified as linear or branched on the basis of their chain architecture. The polymer chains in linear polymers have a long chain-like structure with minimal to no branching at all. Even if a polymer features large substituent groups on the monomer, which appear as branches to the skeleton, it is not considered a branched polymer. A branched polymer contains secondary polymer chains that arise from the main polymer chain. The branching occurs when the polymer growth shifts from...
2.6K
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
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
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
Polymer Classification: Stereospecificity
2.4K
Polymerization generates chiral centers along the entire backbone of a polymer chain. Accordingly, the stereochemistry of the substituent group has a significant effect on polymer properties. Polymers formed from monosubstituted alkene monomers feature chiral carbons at every alternate position in the polymer backbone. Relative to the predominant orientation of substituents at the adjacent chiral carbons, the polymer can exist in three different configurations: isotactic, syndiotactic, and...
2.4K
Relation between Poisson's ratio, Modulus of Elasticity and Modulus of Rigidity
249
Deformation occurs in axial and transverse directions when an axial load is applied to a slender bar. This deformation impacts the cubic element within the bar, transforming it into either a rectangular parallelepiped or a rhombus, contingent on its orientation. This transformation process induces shearing strain. Axial loading elicits both shearing and normal strains. Applying an axial load instigates equal normal and shearing stresses on elements oriented at a 45° angle to the load axis.
249

