Saleh O A, McIntosh D B, Pincus P, Ribeck N
Materials Department and BMSE Program, University of California, Santa Barbara, California 93106, USA.
Phys Rev Lett. 2009 Feb 13;102(6):068301. doi: 10.1103/PhysRevLett.102.068301. Epub 2009 Feb 11.
We reconcile single-molecule force-extension data with scaling theories of polymer elasticity: measurements of denatured single-stranded DNA show a regime where the extension grows as a nonlinear power law with force, in accordance with "tensile blob" models. Analysis of the salt dependence of this regime indicates that the polymer's Kuhn length is proportional to the Debye length; this contradicts the Odijk-Skolnick-Fixman theory, but agrees with other predictions. Finally, we identify a Theta condition of the polymer, and find that the wormlike chain model best describes the polymer's elasticity at this point.
我们将单分子力-伸长数据与聚合物弹性的标度理论进行了协调：对变性单链DNA的测量表明，存在一个区域，其中伸长随力呈非线性幂律增长，这与“拉伸链段”模型一致。对该区域盐依赖性的分析表明，聚合物的库恩长度与德拜长度成正比；这与奥迪克-斯科尔尼克-菲克斯曼理论相矛盾，但与其他预测相符。最后，我们确定了聚合物的θ条件，并发现蠕虫状链模型最能描述此时聚合物的弹性。
