Texas Tech University, Lubbock, TX, USA.
North Carolina State University, Raleigh, NC, USA.
Sci Rep. 2023 Mar 14;13(1):4224. doi: 10.1038/s41598-023-31074-0.
Ultra-stable fluoropolymer glasses were created using vacuum pyrolysis deposition that show large fictive temperature T reductions relative to the glass transition temperature T of the rejuvenated material. T was also found to be 11.4 K below the dynamic VFT temperature T. Glass films with various thickness (200-1150 nm) were deposited onto different temperature substrates. Glassy films were characterized using rapid-chip calorimetry, Fourier-transform infrared spectroscopy and intrinsic viscosity measurements. Large enthalpy overshoots were observed upon heating and a T reduction of 62.6 K relative to the T of 348 K was observed. This reduction exceeds values reported for a 20-million-year-old amber and another amorphous fluoropolymer and is below the putative Kauzmann temperature T for the material as related to T. These results challenge the importance of the Kauzmann paradox in glass-formation and illustrates a powerful method for the exploration of material dynamics deep in the glassy state (T < T < T).
采用真空热解沉积法制备了超稳定氟聚合物玻璃，相对于材料的玻璃化转变温度 T，其虚拟温度 T 有较大的降低。还发现 T 比动态 Vogel-Fulcher-Tammann（VFT）温度 T 低 11.4 K。在不同温度的基底上沉积了不同厚度（200-1150nm）的玻璃膜。使用快速芯片量热法、傅里叶变换红外光谱和特性粘度测量对玻璃膜进行了表征。在加热过程中观察到较大的焓过冲，相对于 348K 的 T，观察到 62.6K 的 T 降低。这种降低超过了报道的 2000 万岁琥珀和另一种非晶态氟聚合物的值，低于与 T 相关的材料的假定 Kauzmann 温度 T。这些结果挑战了玻璃形成中 Kauzmann 悖论的重要性，并说明了一种探索玻璃态（T<T<T）下材料动力学的强大方法。
