Molecular dynamics (MD) of polycarbonate is used to understand the molecular bases of ratcheting and sensitivity to variation in polymer chain lengths. We find that ratcheting is almost insensitive to molecular weight in mono-disperse systems, but not in poly-disperse systems. MD-to-continuum measures show that molecular motions of short chains in poly-dispersed systems are distinct from longer-sized chains, and, via easily detangling, moving, and relaxing, become compact even when the bulk expands. This indicates that short chains in poly-disperse systems play a central role in creating non-affine volume that accelerates ratcheting, while having no influence in short-chained mono-disperse systems.

聚碳酸酯的分子动力学 (MD) 用于了解棘轮的分子基础和对聚合物链长度变化的敏感性。我们发现棘轮在单分散系统中几乎对分子量不敏感，但在多分散系统中则不然。MD-to-continuum 测量表明，多分散系统中短链的分子运动与长链不同，并且通过轻松解开、移动和松弛，即使体积膨胀也变得紧凑。这表明多分散系统中的短链在产生加速棘轮的非仿射体积方面起着核心作用，而对短链单分散系统没有影响。