We have examined the effect of crowder particle charge on macromolecular structure, studied via small-angle neutron scattering, and translational dynamics, studied via pulsed-field gradient NMR, in addition to bulk viscosity measurements, in a polymer macromolecule (polyethylene glycol)—nanoparticle crowder (polysucrose, Ficoll70) model system, in the case where polymer size and crowder size are comparable. While there are modest effects of crowder charge on polymer dynamics at relatively low packing fractions, there is only a tiny effect at the high packing fractions that represent the limit of molecular crowding. We find, via different measures of macromolecular mobility, that the mobility of the flexible polymer in the crowding limit is 10–100 times larger than that of the compact, spherical crowder in spite of their similar size, implying that the flexible polymer chain is able to squeeze through crowder interstices.

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大分子拥挤模型聚合物-胶体系统中拥挤电荷的影响：聚合物的结构和动力学

我们已经研究了高分子聚合物（聚乙二醇）-纳米颗粒中拥挤粒子电荷对大分子结构的影响（通过小角度中子散射研究）和平移动力学（通过脉冲场梯度NMR研究）以及体积粘度测量结果聚合物大小和拥挤物大小可比的情况下，使用拥挤物（聚蔗糖，Ficoll70）模型系统。虽然在相对较低的填充分数下拥挤电荷对聚合物动力学有适度的影响，但在高填充分数下仅存在很小的影响，这代表了分子拥挤的极限。我们发现，通过 高分子迁移率的不同测量方法，尽管它们的大小相似，但在拥挤极限中柔性聚合物的迁移率比紧凑的球形拥挤器大10–100倍，这意味着柔性聚合物链能够通过拥挤器挤压间隙。