Attractions between hard colloidal spheres in semiflexible polymer solutions
Attractions between hard colloidal spheres in semiflexible polymer solutions
复制标题
半柔性聚合物溶液中硬胶体球之间的吸引力
DOI：
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发表时间：
2000
期刊：
影响因子：
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通讯作者：
A. Yodh
中科院分区：
文献类型：
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作者：
R. Verma;J. Crocker;T. Lubensky;A. Yodh
我们探索了在浸泡在DNA的非吸附聚合物溶液中的硬胶体球体之间产生的耗尽吸引力。我们将两个1.25μm的二氧化硅微球限制在扫描光钳中，并定量研究了它们在不同浓度的双链DNA溶液中的相互作用势。得到的电势在深度和范围上表现出变化，这与θ点附近的半柔性聚合物的预期标度行为一致。特别是，我们清楚地观察到了从高斯线圈的稀溶液到由两点碰撞主导的弱起伏半稀区的交叉(Schaefer，D.W.；Joanny，J.F.；Pincus，P.Macromoles，1980，13,1280−1289)。我们还对这些体系的浅仓−Oosawa模型进行了定量测试，结果表明该模型既可用于半稀状态，也可用于稀化状态。在固定的DNA浓度下，我们发现离子凝聚的粒子间势的范围和深度没有明显的变化。
We explore the depletion attractions that arise between hard colloidal spheres immersed in a nonadsorbing polymer solution of DNA. We spatially confine two 1.25 μm silica spheres in a scanning optical tweezer and quantitatively examine their interaction potential in double-stranded DNA solutions of different concentrations. The potentials obtained display variations in depth and range that are consistent with scaling behavior expected for semiflexible polymers near the θ-point. In particular, we clearly observe the crossover from a dilute solution of Gaussian coils to the weakly fluctuating semidilute regime dominated by two-point collisions (Schaefer, D. W.; Joanny, J. F.; Pincus, P. Macromolecules 1980, 13, 1280−1289). We also quantitatively test the Asakura−Oosawa model for these systems and show that it may be used in both the semidilute as well as the dilute regime. At fixed DNA concentration, we find that the range and depth of the interparticle potentials do not change significantly for ionic conce...