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

作　　者：Lin Cao Li-Jian Song Ya-Ru Cao Wei Xu Jun-Tao Huo Yun-Zhuo Lv Jun-Qiang Wang 曹琳;宋丽建;曹亚茹;许巍;霍军涛;吕云卓;王军强(School of Materials Science and Engineering,Dalian Jiaotong University,Dalian 116028,China;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;Center of Materials Science and Optoelectronics Engineering,University of Chinese Academy of Sciences,Beijing 100049,China)

机构地区：[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

出　　处：《Chinese Physics B》2021年第7期376-381,共6页中国物理B（英文版）

基　　金：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);the Natural Science Foundation of Ningbo City(Grant No.202003N4354)。

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 

分 类 号：TQ171.1[化学工程—玻璃工业]