Department of Materials and Interfaces, Weizmann Institute of Science, Rehovot 76100, Israel.
Phys Rev E. 2017 May;95(5-1):052415. doi: 10.1103/PhysRevE.95.052415. Epub 2017 May 25.
We theoretically predict the nonlinear elastic responses of polydisperse biopolymer gels to uniaxial compression. We analyze the competition between compressive stiffening due to polymer densification by out-going solvent flow and compressive softening due to continuous polymer buckling. We point out that the polydispersity in polymer lengths can result in an intrinsic, equilibrium mode of nonaffine compression: nonuniform strain but with uniform force distribution, which is found to be more energetically preferable than affine deformation. In this case, the gel softens significantly after the onset of polymer buckling at small compression, but as compression increases, densification-induced stiffening becomes important and a modulus plateau should be observed for a large range of strain. We also relate our results to recent compression experiments on collagen gels and fibrin gels.
我们从理论上预测了多分散生物聚合物凝胶在单轴压缩下的非线性弹性响应。我们分析了由于溶剂流出导致聚合物致密化引起的压缩变硬和由于连续聚合物屈曲引起的压缩软化之间的竞争。我们指出，聚合物长度的多分散性可能导致内在的、平衡的非仿射压缩模式：不均匀的应变，但均匀的力分布，这比仿射变形更具能量优势。在这种情况下，在聚合物屈曲开始后，凝胶在小压缩下会显著软化，但随着压缩的增加，由于致密化引起的变硬变得重要，并且在大应变范围内应该观察到模量平台。我们还将我们的结果与最近对胶原蛋白凝胶和纤维蛋白凝胶的压缩实验进行了关联。
