Effects of Topological Constraints on Penetration Structures of Semi-Flexible Ring Polymers

• Published in: Polymers 2020-11, Vol.12 (11), p.2659
• Main Authors: Guo, Fuchen, Li, Ke, Wu, Jiaxin, He, Linli, Zhang, Linxi
• Format: Article
• Language: English
• ISSN: 2073-4360; 2073-4360
• DOI: 10.3390/polym12112659

The effects of topological constraints on penetration structures of semi-flexible ring polymers in a melt are investigated using molecular dynamics simulations, considering simultaneously the effects of the chain stiffness. Three topology types of rings are considered: 0 -knot (the unknotted), 3 -knot and 6 -knot ring polymers, respectively. With the improved algorithm to detect and quantify the inter-ring penetration (or inter-ring threading), the degree of ring threading does not increase monotonously with the chain stiffness, existing a peak value at the intermediate stiffness. It indicates that rings interpenetrate most at intermediate stiffness where there is a balance between coil expansion (favoring penetrations) and stiffness (inhibiting penetrations). Meanwhile, the inter-ring penetration would be suppressed with the knot complexity of the rings. The analysis of effective potential between the rings provides a better understanding for this non-monotonous behavior in inter-ring penetration.