Materials Science and Engineering Program, University of Houston, Houston, Texas 77204, United States.
William A. Brookshire Department of Chemical and Biomolecular Engineering, University of Houston, Houston, Texas 77204, United States.
ACS Macro Lett. 2021 May 18;10(5):518-524. doi: 10.1021/acsmacrolett.0c00898. Epub 2021 Apr 13.
We show that dispersity () markedly alters the conformation of spherical polymer brushes. The average lengths () of poly(-butyl acrylate) (PBA) brushes of varying grafted to nanoparticles were measured using dynamic light scattering. In the semidilute polymer brush (SDPB) regime, the of PBA and polymers from earlier studies of various could be cleanly collapsed onto a master curve as a function of the scaling variable σ, where is the weight-average degree of polymerization and σ is the grafting density. In the concentrated polymer brush (CPB) regime, however, collapsed onto a bifurcated curve as a function of the scaling variable σ, indicating more strongly affects the average length of brushes with low σ. We propose that the stretching of the stem near the particle surface due to interchain interactions in the CPB regime leads to greater in broad dispersity brushes of low but not high σ.
我们表明，分散性（dispersity）显著改变了球形聚合物刷的构象。使用动态光散射测量了不同 接枝到纳米粒子上的聚（-丁基丙烯酸酯）（PBA）刷的平均长度（）。在半浓聚合物刷（SDPB）区，PBA 的 和来自先前各种 聚合物的 可以干净地折叠成一个主曲线作为标度变量 σ 的函数，其中 是重均聚合度，σ 是接枝密度。然而，在浓聚合物刷（CPB）区， 作为标度变量 σ 的函数折叠成一个分叉曲线，表明 更强烈地影响具有低 σ 的刷的平均长度。我们提出，在 CPB 区由于链间相互作用导致的靠近粒子表面的茎的拉伸导致低 σ 的宽分散性刷的 更大，但高 σ 的则不然。
