论文题目：Fully Controllable Structural Phase Transition in Thermomechanical Molecular Crystals with a Very Small Thermal Hysteresis

论文作者：Yulong Duan, Sergey Semin, Paul Tinnemans, Jialiang Xu*, Theo Rasing

发表期刊：Small, 17(14), 2006757, 2021    

Abstract： 

The construction of a practical crystalline molecular machine faces two  challenges: to realize a collective molecular movement, and to amplify  this movement into a precisely controlled mechanical response in real  time and space. Thermosalient single crystals display cooperative  molecular movements that are converted to strong macroscopic mechanical  responses or shape deformations during temperature-induced structural  phase transitions. However, these collective molecular movements are  hard to control once initiated, and often feature thermal hystereses  that are larger than 10 degrees C, which greatly hamper their practical  applications. Here, it is demonstrated that the phase boundaries of the  thermomechanical molecular crystal based on a fluorenone derivative  4-DBpFO can be used to finely control its structural phase transition.  When this phase transition is triggered at two opposite crystal faces,  it is accompanied by two parallel phase boundaries that can be  temperature controlled to move forward, backward, or to halt,  benefitting from the stored elastic energy between the parallel  boundaries. Moreover, the thermal hysteresis is greatly decreased to 2-3  degrees C, which allows for circular heating/cooling cycles that can  produce a continuous work output.