Chain ends excite polymer cooperative motion.

ABSTRACT: Among glasses, polymers stand out as the chain connectivity endows them with distinct properties in glass formation, among them the transition temperature (T_g) and dynamic fragility (m) varying with chain length. Here, we resolve the nature of the chain length-dependent behaviors, revealing the strong correlation between the number of chain ends within the cooperatively rearranging region and glassy properties including T_g and m. The correlations suggest a simple yet common mechanism of glass formation for the chain molecules, i.e., fast-relaxing chain ends alleviate the requirements of cooperativity for structural rearrangement, thus facilitating the cooperative motion that reduces T_g and m as chain length is short

SUBMITTER: Xu Q 

PROVIDER: S-EPMC12652251 | biostudies-literature | 2025 Nov

REPOSITORIES: biostudies-literature