Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139, USA. Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
Science. 2016 Sep 16;353(6305):1264-8. doi: 10.1126/science.aag0184.
Elasticity, one of the most important properties of a soft material, is difficult to quantify in polymer networks because of the presence of topological molecular defects in these materials. Furthermore, the impact of these defects on bulk elasticity is unknown. We used rheology, disassembly spectrometry, and simulations to measure the shear elastic modulus and count the numbers of topological "loop" defects of various order in a series of polymer hydrogels, and then used these data to evaluate the classical phantom and affine network theories of elasticity. The results led to a real elastic network theory (RENT) that describes how loop defects affect bulk elasticity. Given knowledge of the loop fractions, RENT provides predictions of the shear elastic modulus that are consistent with experimental observations.
弹性是软物质最重要的性质之一，但由于这些材料中存在拓扑分子缺陷，聚合物网络中的弹性很难定量。此外，这些缺陷对体弹性的影响尚不清楚。我们使用流变学、拆解光谱和模拟来测量一系列聚合物水凝胶的剪切弹性模量，并计算各种阶拓扑“环”缺陷的数量，然后使用这些数据来评估弹性的经典幻影和仿射网络理论。结果得出了一个真实的弹性网络理论（RENT），该理论描述了环缺陷如何影响体弹性。给定环分数的知识，RENT 提供的剪切弹性模量预测与实验观察结果一致。
