Low molecular weight thiol-terminated poly(ethylene glycol) (PEG) (M ≈ 800) has been grafted onto a high molecular weight methylcellulose (MC, M_w ≈ 150000) by a facile thiol–ene click reaction; graft densities varied from 0.7% to 33% (grafts per anhydroglucose unit). Static and dynamic light scattering reveals that the overall radius of the chain increases systematically with graft density, in a manner in excellent agreement with theory. As the contour length remains unchanged, it is apparent that grafting leads to an increase in the persistence length of this semiflexible copolymer, by as much as a factor of 4. These results represent the first experimental verification of the excluded volume theory at low grafting densities, and demonstrate a promising synthetic platform for systematically increasing the persistence length of a model semiflexible, water-soluble polymer.

中文翻译：

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甲基纤维素的构象作为聚（乙二醇）接枝密度的函数

低分子量硫醇封端聚乙二醇 (PEG) ( M ≈ 800) 已接枝到高分子量甲基纤维素 (MC, M _w≈ 150000) 通过简单的硫醇-烯点击反应；接枝密度从 0.7% 到 33% 不等（每个脱水葡萄糖单位的接枝数）。静态和动态光散射表明，链的总半径随接枝密度而系统地增加，这与理论非常吻合。由于轮廓长度保持不变，很明显接枝导致这种半柔性共聚物的持久长度增加了多达 4 倍。这些结果代表了排除体积理论在低接枝密度下的第一次实验验证，并展示了一个有前途的合成平台，用于系统地增加模型半柔性水溶性聚合物的持久长度。