Mixed equilibrium/nonequilibrium effects govern surface mobility in polymer glasses
| Autor: | Xu, Jianquan, Ghanekarade, Asieh, Li, Li, Zhu, Huifeng, Yuan, Hailin, Yan, Jinsong, Simmons, David S., Tsui, Ophelia K. C., Wang, Xinping |
|---|---|
| Rok vydání: | 2024 |
| Předmět: | |
| Druh dokumentu: | Working Paper |
| Popis: | The temperature at which supercooled liquids turn into solid-like glasses ($T_g$) can change at the free surface, affecting the properties of nanostructured glasses and their applications. However, inadequate experimental resolution to determine the $T_g$ gradient and a longstanding debate over the role of nonequilibrium effects have hindered fundamental understanding of this phenomenon. Using spatially resolved $T_g$ measurements and molecular dynamics simulations, we reveal a crossover from equilibrium behavior to a new regime of near-surface nonequilibrium glass physics on cooling. This crossover causes the form of the nonequilibrium $T_g$ gradient to change, highlighting the need to include these physics for rational understanding of the properties of realistic nanostructured glass-forming materials. They also potentially recast the interpretation of decades of experimental data on nanoconfined glasses. Comment: This PDF file includes two documents: The first is the main manuscript, which consists of 13 pages and 4 figures. The second document is the supplementary materials, which contains 25 pages, 8 figures, and 3 tables |
| Databáze: | arXiv |
| Externí odkaz: |
|