Solution size variation of linear and dendritic bis-MPA analogs using DOSY- 1 H NMR
Solution size variation of linear and dendritic bis-MPA analogs using DOSY- 1 H NMR
复制标题
使用 DOSY- 1 H NMR 观察线性和树枝状双 MPA 类似物的溶液尺寸变化
DOI：
10.1039/d0py01070g
复制
发表时间：
2021
影响因子：
4.6
通讯作者：
Grayson, Scott M.
中科院分区：
文献类型：
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作者：
Kareem, Oluwapelumi O.;Rahmani, Farzin;Hyman, Jason A.;Keller, Christopher B.;Pasquinelli, Melissa A.;Savin, Daniel A.;Grayson, Scott M.
树枝状大分子是一种球形、多功能、单分散的大分子，具有完美的结构保真度。它们的结构是由一系列分支的聚合物臂组成的，这些聚合物臂由“楔形”组成，从中心核心发出。它们的结构包含位于其外围的高密度官能团，称为“外壳”。由于它们的球形结构，假设树枝状聚合物的相对“尺寸”在溶剂之间不会大幅波动。这可能是由于支化臂或楔形物由于来自支化的空间位阻而不能显著膨胀或塌陷（与类似的线性聚合物相比），特别是在较高的代数下。相反，预期与树枝状聚合物类似物具有相似分子量的线性聚合物将具有取决于溶剂-聚合物相互作用的更大程度的尺寸变化。这源于其固有的灵活性和更大的构象灵活性。对于这项调查，类似的树枝状和线性双MPA聚酯以及聚（己内酯）（PCL）进行了分析，使用尺寸测量技术，包括凝胶渗透色谱法（GPC）和扩散有序光谱-核磁共振（DOSY-1H NMR）。
Dendrimers are globular, multi-functional, monodisperse macromolecules with perfect structure fidelity. Their architecture is composed of a series of branched polymeric arms, composed within “wedges”, that emanate from a central core. Their structure contains a high density of functional groups located at their periphery, referred to as the “outer shell”. Due to their globular structure, it is assumed that the relative “size” of a dendrimer does not fluctuate greatly between solvents. This may be due to the inability of the branched arms, or wedges, to significantly expand or collapse (comparative to analogous linear polymers) owing to steric barriers from branching, especially at higher generations. In contrast, it is expected that a linear polymer, of similar molecular weight to a dendrimer analog, would have a greater degree of size variation dependent on solvent-polymer interactions. This stems from its innate flexibility and greater conformational flexibility. For this investigation, analogous dendritic and linear bis-MPA polyesters as well as poly(caprolactone) (PCL) were analyzed using size-measuring techniques including gel permeation chromatography (GPC) and diffusion ordered spectroscopy-nuclear magnetic resonance (DOSY-1H NMR).