Bolisetty S, Airaud C, Xu Y, Müller A H E, Harnau L, Rosenfeldt S, Lindner P, Ballauff M
Physikalische Chemie I, University of Bayreuth, D-95440 Bayreuth, Germany.
Phys Rev E Stat Nonlin Soft Matter Phys. 2007 Apr;75(4 Pt 1):040803. doi: 10.1103/PhysRevE.75.040803. Epub 2007 Apr 30.
We study bottle-brush macromolecules in a good solvent by small-angle neutron scattering (SANS), static light scattering (SLS), and dynamic light scattering (DLS). These polymers consist of a linear backbone to which long side chains are chemically grafted. The backbone contains about 1600 monomer units (weight average) and every second monomer unit carries side chains with approximately 60 monomer units. The SLS and SANS data extrapolated to infinite dilution lead to the form factor of the polymer that can be described in terms of a wormlike chain with a contour length of 380 nm and a persistence length of 17.5 nm. An analysis of the DLS data confirms these model parameters. The scattering intensities taken at finite concentration can be modeled using the polymer reference interaction site model. It reveals a softening of the bottle-brush polymers caused by their mutual interaction. We demonstrate that the persistence decreases from 17.5 nm down to 5 nm upon increasing the concentration from dilute solution to the highest concentration (40.59 gl) under consideration. The observed softening of the chains is comparable to the theoretically predicted decrease of the electrostatic persistence length of linear polyelectrolyte chains at finite concentrations.
我们通过小角中子散射（SANS）、静态光散射（SLS）和动态光散射（DLS）研究了在良溶剂中的刷状大分子。这些聚合物由线性主链组成，长侧链化学接枝在主链上。主链包含约1600个单体单元（重均），每第二个单体单元带有约60个单体单元的侧链。外推到无限稀释的SLS和SANS数据得出聚合物的形状因子，其可以用轮廓长度为380nm、持久长度为17.5nm的蠕虫状链来描述。对DLS数据的分析证实了这些模型参数。在有限浓度下获取的散射强度可以使用聚合物参考相互作用位点模型进行建模。结果表明，刷状聚合物由于其相互作用而发生软化。我们证明，在从稀溶液到所考虑的最高浓度（40.59g/l）的浓度增加过程中，持久长度从17.5nm降至5nm。观察到的链的软化与理论预测的有限浓度下线性聚电解质链的静电持久长度的降低相当。
