中国物理B ›› 2021, Vol. 30 ›› Issue (7): 76103-076103.doi: 10.1088/1674-1056/abf919

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Small activation entropy bestows high-stability of nanoconfined D-mannitol

Lin Cao(曹琳)1,2,3, Li-Jian Song(宋丽建)2,3,†, Ya-Ru Cao(曹亚茹)2,3, Wei Xu(许巍)2,3, Jun-Tao Huo(霍军涛)2,3, Yun-Zhuo Lv(吕云卓)1,‡, and Jun-Qiang Wang(王军强)2,3,§   

  1. 1 School of Materials Science and Engineering, Dalian Jiaotong University, Dalian 116028, China;
    2 CAS Key Laboratory of Magnetic Materials and Devices, and Zhejiang Province Key Laboratory of Magnetic Materials and Application Technology, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences(CAS), Ningbo 315201, China;
    3 Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, China
  • 收稿日期:2021-03-08 修回日期:2021-04-06 接受日期:2021-04-19 出版日期:2021-06-22 发布日期:2021-07-09
  • 通讯作者: Li-Jian Song, Yun-Zhuo Lv, Jun-Qiang Wang E-mail:songlj@nimte.ac.cn;yunzhuohit@gmail.com;jqwang@nimte.ac.cn
  • 基金资助:
    Project supported by the National Natural Science Foundation of China (Grant Nos. 52001319, 52071327, 51922102, 51771216, and 51701230), the Natural Science Foundation of Zhejiang Province, China (Grant Nos. LR18E010002), the Ningbo 2025 Science and Technology Innovation Project (Grant No. 2019B10051), and the Natural Science Foundation of Ningbo City (Grant No. 202003N4354).

Small activation entropy bestows high-stability of nanoconfined D-mannitol

Lin Cao(曹琳)1,2,3, Li-Jian Song(宋丽建)2,3,†, Ya-Ru Cao(曹亚茹)2,3, Wei Xu(许巍)2,3, Jun-Tao Huo(霍军涛)2,3, Yun-Zhuo Lv(吕云卓)1,‡, and Jun-Qiang Wang(王军强)2,3,§   

  1. 1 School of Materials Science and Engineering, Dalian Jiaotong University, Dalian 116028, China;
    2 CAS Key Laboratory of Magnetic Materials and Devices, and Zhejiang Province Key Laboratory of Magnetic Materials and Application Technology, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences(CAS), Ningbo 315201, China;
    3 Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, China
  • Received:2021-03-08 Revised:2021-04-06 Accepted:2021-04-19 Online:2021-06-22 Published:2021-07-09
  • Contact: Li-Jian Song, Yun-Zhuo Lv, Jun-Qiang Wang E-mail:songlj@nimte.ac.cn;yunzhuohit@gmail.com;jqwang@nimte.ac.cn
  • Supported by:
    Project supported by the National Natural Science Foundation of China (Grant Nos. 52001319, 52071327, 51922102, 51771216, and 51701230), the Natural Science Foundation of Zhejiang Province, China (Grant Nos. LR18E010002), the Ningbo 2025 Science and Technology Innovation Project (Grant No. 2019B10051), and the Natural Science Foundation of Ningbo City (Grant No. 202003N4354).

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摘要： It has been a long-standing puzzling problem that some glasses exhibit higher glass transition temperatures (denoting high stability) but lower activation energy for relaxations (denoting low stability). In this paper, the relaxation kinetics of the nanoconfined D-mannitol (DM) glass was studied systematically using a high-precision and high-rate nanocalorimeter. The nanoconfined DM exhibits enhanced thermal stability compared to the free DM. For example, the critical cooling rate for glass formation decreases from 200 K/s to below 1 K/s; the Tg increases by about 20 K-50 K. The relaxation kinetics is analyzed based on the absolute reaction rate theory. It is found that, even though the activation energy E* decreases, the activation entropy S* decreases much more for the nanoconfined glass that yields a large activation free energy G* and higher thermal stability. These results suggest that the activation entropy may provide new insights in understanding the abnormal kinetics of nanoconfined glassy systems.

关键词: D-mannitol glass, confinement, relaxation, activation entropy

Abstract: It has been a long-standing puzzling problem that some glasses exhibit higher glass transition temperatures (denoting high stability) but lower activation energy for relaxations (denoting low stability). In this paper, the relaxation kinetics of the nanoconfined D-mannitol (DM) glass was studied systematically using a high-precision and high-rate nanocalorimeter. The nanoconfined DM exhibits enhanced thermal stability compared to the free DM. For example, the critical cooling rate for glass formation decreases from 200 K/s to below 1 K/s; the Tg increases by about 20 K-50 K. The relaxation kinetics is analyzed based on the absolute reaction rate theory. It is found that, even though the activation energy E* decreases, the activation entropy S* decreases much more for the nanoconfined glass that yields a large activation free energy G* and higher thermal stability. These results suggest that the activation entropy may provide new insights in understanding the abnormal kinetics of nanoconfined glassy systems.

Key words: D-mannitol glass, confinement, relaxation, activation entropy

中图分类号:  (Glasses)

  • 61.43.Fs
61.20.Lc (Time-dependent properties; relaxation) 64.70.P- (Glass transitions of specific systems)