We present a systematic study of flexible cylindrical brush-shaped macromolecules in a good solvent by small-angle neutron scattering (SANS), static light scattering (SLS), and by dynamic light scattering (DLS) in dilute and semi-dilute solution. The SLS and SANS data extrapolated to infinite dilution lead to the shape of the polymer that can be modeled in terms of a worm-like chain with a contour length of 380 nm and a persistence length of 17.5 nm. SANS data taken at higher polymer concentration were evaluated by using the polymer reference interaction site model (PRISM). We find that the persistence length reduce from 17.5 nm at infinite dilution to 5.3 nm at the highest concentration (volume fraction 0.038). This is comparable with the decrease of the persistence length in semi-dilute concentration predicted theoretically for polyelectrolytes. This finding reveals a softening of stiffness of the polymer brushes caused by their mutual interaction.

中文翻译：

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圆柱形聚合物刷在稀和半稀溶液中的相互作用

我们通过小角中子散射 (SANS)、静态光散射 (SLS) 和动态光散射 (DLS) 在稀和半稀溶液中对良好溶剂中的柔性圆柱刷状大分子进行了系统研究。SLS 和 SANS 数据外推到无限稀释导致聚合物的形状，可以根据蠕虫状链建模，轮廓长度为 380 nm，持久长度为 17.5 nm。通过使用聚合物参考相互作用位点模型 (PRISM) 评估在较高聚合物浓度下获取的 SANS 数据。我们发现持久性长度从无限稀释时的 17.5 nm 减少到最高浓度时的 5.3 nm（体积分数 0.038）。这与理论上预测的聚电解质的半稀释浓度的持续时间的减少相当。