水溶性可逆新 ((III) 协调聚合物的线性质学
Tina Vermonden1, Mies J van Steenbergen, Nicolaas A M Besseling
1Laboratory of Organic Chemistry, Dutch Polymer Institute/Wageningen University, Dreijenplein 8, 6703 HB Wageningen, The Netherlands.
Journal of the American Chemical Society
|December 2, 2004
概括
本研究探讨了由新(III) 离子形成的可逆协调聚合物网络. 这些粘弹性材料表现出线性平衡聚合物动力学和热可逆凝行为.
科学领域:
- 聚合物化学 聚合物化学
- 材料科学 材料科学 材料科学
- 类风病学 类风病学 类风病学
背景情况:
- 协调聚合物具有可调节的特性.
- 了解它们的质性行为对于应用至关重要.
- 可逆网络对自我愈合和对刺激有反应的材料有兴趣.
研究的目的:
- 为了研究新型可逆协调聚合物网络的整形学.
- 描述这些网络在水溶液中的粘弹性特性.
- 为了确定度和温度对网络动态的影响.
主要方法:
- 进行了rheological测量 (粘性弹性,放松时间,粘度).
- 麦克斯韦模型被用来描述材料的行为.
- 进行了度和温度依赖性研究.
主要成果:
- 在高度下,聚合物网络表现出粘性弹性.
- 材料性能与凯特斯对线性平衡聚合物的模型保持一致.
- 这些凝表现出热可逆性,在冷却后立即恢复性能.
结论:
- 研究的网络表现为具有最小交叉连接的线性平衡聚合物.
- 热可逆性允许在高温下具有类似液体的行为.
- 对于聚合物动态,确定了49kJ/mol的激活能量.
相关概念视频
Formation of Complex Ions
A type of Lewis acid-base chemistry involves the formation of a complex ion (or a coordination complex) comprising a central atom, typically a transition metal cation, surrounded by ions or molecules called ligands. These ligands can be neutral molecules like H2O or NH3, or ions such as CN− or OH−. Often, the ligands act as Lewis bases, donating a pair of electrons to the central atom. These types of Lewis acid-base reactions are examples of a broad subdiscipline called coordination...
Structural Isomerism
Isomerism in Complexes
Isomers are different chemical species that have the same chemical formula. Structural isomerism of coordination compounds can be divided into two subcategories, the linkage isomers and coordination-sphere isomers.
Linkage isomers occur when the coordination compound contains a ligand that can bind to the transition metal center through two different atoms. For example, the CN− ligand can bind through the carbon atom or through the nitrogen atom. Similarly, SCN− can be...
Isomers are different chemical species that have the same chemical formula. Structural isomerism of coordination compounds can be divided into two subcategories, the linkage isomers and coordination-sphere isomers.
Linkage isomers occur when the coordination compound contains a ligand that can bind to the transition metal center through two different atoms. For example, the CN− ligand can bind through the carbon atom or through the nitrogen atom. Similarly, SCN− can be...
Stereoisomerism
Isomerism in Complexes
Isomers are different chemical species that have the same chemical formula.
Transition metal complexes often exist as geometric isomers, in which the same atoms are connected through the same types of bonds but with differences in their orientation in space. Coordination complexes with two different ligands in the cis and trans positions from a ligand of interest form isomers. For example, the octahedral [Co(NH3)4Cl2]+ ion has two isomers (Figure 1) In the cis...
Isomers are different chemical species that have the same chemical formula.
Transition metal complexes often exist as geometric isomers, in which the same atoms are connected through the same types of bonds but with differences in their orientation in space. Coordination complexes with two different ligands in the cis and trans positions from a ligand of interest form isomers. For example, the octahedral [Co(NH3)4Cl2]+ ion has two isomers (Figure 1) In the cis...
Valence Bond Theory
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...
[3,3] Sigmatropic Rearrangement of 1,5-Dienes: Cope Rearrangement
The Cope rearrangement is classified as a [3,3] sigmatropic shift in 1,5-dienes, leading to a more stable, isomeric 1,5-diene. The reaction involves a concerted movement of six electrons, four from two π bonds and two from a σ bond, via an energetically favorable chair-like transition state.
Complexation Equilibria: Overview
Complexation reactions take place when dative or coordinate covalent bonds form between metal ions and ligands. The compounds formed in these reactions are called coordination compounds. The number of bonds formed between the metal ion and the ligands is called its coordination number. Generally, most metal ions in an aqueous solution are solvated by water molecules and thus exist as aqua complexes.
The equilibrium constant of the complexation reaction is represented as the formation constant...
The equilibrium constant of the complexation reaction is represented as the formation constant...


