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相关概念视频

Polymers02:34

Polymers

The word polymer is derived from the Greek words “poly” which means “many” and “mer” which means “parts”. Polymers are long chains of molecules composed of repeating units of smaller molecules, known as monomers. They either occur naturally, such as DNA and proteins, or can be constructed synthetically, like plastics. They have varied structural characteristics, such as linear chains, branched chains, or complex networks, that contribute to the properties that they exhibit. Additionally,...
Characteristics and Nomenclature of Copolymers01:24

Characteristics and Nomenclature of Copolymers

Copolymers are the products obtained from the polymerization of multiple monomer species. So, in a polymer chain itself, there can be multiple repeating units that come from different monomers. The process of synthesizing a polymer from different monomer species is called copolymerization. When two monomers are involved, the polymer is known as a bipolymer. Polymers with three and four monomers are termed terpolymers and quaterpolymers, respectively. Figure 1 depicts the copolymerization of...
Polymers: Molecular Weight Distribution01:10

Polymers: Molecular Weight Distribution

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.
Polymer Classification: Crystallinity01:21

Polymer Classification: Crystallinity

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...
Molecular Weight of Step-Growth Polymers01:08

Molecular Weight of Step-Growth Polymers

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...
Determination of Molar Masses of Polymers I01:24

Determination of Molar Masses of Polymers I

Polymerization produces macromolecules with a range of chain lengths due to the random nature of molecular growth processes. As chains form and terminate at different stages, a single polymer sample contains molecules of varying sizes rather than a uniform structure. This variability is described using average molar masses and distribution-related parameters, which together provide a comprehensive understanding of polymer characteristics.The distribution of molar masses plays a critical role in...

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相关实验视频

Updated: Jul 26, 2026

Controlling the Size, Shape and Stability of Supramolecular Polymers in Water
16:24

Controlling the Size, Shape and Stability of Supramolecular Polymers in Water

Published on: August 2, 2012

切换具有多个长度尺度的超分子聚合物材料.

Ruokolainen1, Makinen, Torkkeli

  • 1J. Ruokolainen and O. Ikkala, Department of Engineering Physics and Mathematics, Helsinki University of Technology, FIN-02015 HUT, Espoo, Finland. R. Makinen, M. Torkkeli, R. Serimaa, Department of Physics, University of Helsinki, Post Office B.

Science (New York, N.Y.)
|May 6, 1998
PubMed
概括

研究人员通过控制相位过渡来创建可调节的聚合物纳米结构. 这些结构表现出温度依赖的电导率,为先进材料提供了潜力.

科学领域:

  • 聚合物科学与工程 聚合物科学与工程
  • 材料科学 材料科学 材料科学
  • 超分子化学 超分子化学

背景情况:

  • 聚合物超分子纳米结构提供可调节的层次顺序-失序和顺序-顺序过渡.
  • 控制这些转换可以同时切换材料中的功能性质.
  • 双块共聚合物为创建复杂的自组装结构提供了一个多功能平台.

研究的目的:

  • 为了证明在聚合物纳米结构中对等级的顺序-失序和顺序-顺序过渡的直接定制.
  • 通过控制微观结构过渡来研究功能性质,特别是电导性的并发切换.
  • 通过使用块共聚合物和超分子复合来实现受控的自我组织结构-结构中的结构.

主要方法:

  • 聚4-乙烯化 (P4VP) 与甲硫酸 (MSA) 的固态测量质子化形成P4VP (MSA) 1.0.0.
  • P4VP (MSA) 1.0的结合复合与甲基.
  • 将MSA和达基复合到微相分离的双块共聚合物聚[styrene-block-(4-vinyl pyridine) 的P4VP块.
  • 观察微相分离,重新进入的闭环宏相分离和高温宏相分离.

主要成果:

  • 在两个不同的长度尺度 (48和350安格斯特罗姆) 的自我组织结构中的结构中实现对等级阶段过渡的系统控制.

更多相关视频

Synthesis and Characterization of Supramolecular Colloids
09:26

Synthesis and Characterization of Supramolecular Colloids

Published on: April 22, 2016

Self-assembling Morphologies Obtained from Helical Polycarbodiimide Copolymers and Their Triazole Derivatives
09:22

Self-assembling Morphologies Obtained from Helical Polycarbodiimide Copolymers and Their Triazole Derivatives

Published on: February 7, 2017

相关实验视频

Last Updated: Jul 26, 2026

Controlling the Size, Shape and Stability of Supramolecular Polymers in Water
16:24

Controlling the Size, Shape and Stability of Supramolecular Polymers in Water

Published on: August 2, 2012

Synthesis and Characterization of Supramolecular Colloids
09:26

Synthesis and Characterization of Supramolecular Colloids

Published on: April 22, 2016

Self-assembling Morphologies Obtained from Helical Polycarbodiimide Copolymers and Their Triazole Derivatives
09:22

Self-assembling Morphologies Obtained from Helical Polycarbodiimide Copolymers and Their Triazole Derivatives

Published on: February 7, 2017

  • 通过微观结构控制,证明了通过微观结构控制诱导导电导率的温度依赖转换的能力.
  • 观察到各种相位分离行为,包括微相位分离,重新进入的闭环宏相位分离和高温宏相位分离.

    • 结论:

    • 聚合物超分子纳米结构具有控制的层次过渡,使可调节的功能性质.
    • 开发的方法允许精确控制跨多个长度尺度的自组装结构.
    • 这种方法为设计具有可切换电导率的材料提供了一条通路,用于先进的应用.