Renkuan Cao, Fan Peng, Hao Sun, Tingyu Xu, Yunhan Zhang, and Researcher Liangbin Li from our team published a research paper in ACS Macro Letters. Using molecular dynamics simulations, this work investigated the kinetic selection mechanism of chain folding during polymer crystallization.
Using the UAPE and CGPVA models, the study revealed that polymer chains undergo directional reptation toward the crystal growth front, demonstrating the existence of an along-chain drag force. This force drives chain disentanglement and facilitates the formation of tight folds. Further analysis established a linear relationship between the tight-fold fraction, pt, and the reciprocal of the entanglement length, 1/Ne, expressed as follows:
pt = p∞ − β/Ne
Here, the parameter β is proportional to the chain rigidity, C∞/b. This relationship indicates that entanglements constrain the physical length scale over which chain segments can fold, whereas chain rigidity determines the difficulty of bending a chain segment into a tight fold. The relationship applies to systems ranging from weakly entangled to equilibrium-entangled states.
This study reveals the critical role of entanglement in connecting molecular topology with crystal morphology, providing a theoretical framework for understanding the kinetic selection of chain folds and regulating polymer crystallization.
This work was supported by the Chinese Academy of Sciences (JZHKYPT-2021-04) and the National Natural Science Foundation of China (22503090).
Cao, R.; Peng, F.; Sun, H.; Xu, T.; Zhang, Y.; Li, L. Kinetic Selection of Chain Folds under Entanglement Constraint. ACS Macro Letters 2026, 15(6), 846–851.
Paper Link: https://doi.org/10.1021/acsmacrolett.6c00161
