Structure-mechanical response of elastic molecular crystals to temperature, pressure and uniaxial strain

  Scheme elastic/plastic bending Copyright: © IfK

Discovery of bending, twisting and shape recovery in molecular crystals in the last 15 years has not only raised eyebrows but generated tremendous interest amongst scientists. The different kinds of macroscopic flexibilities have been successfully obtained in materials where weak intermolecular interactions dominate the crystal packing. Recent discoveries of wave-guide, piezoelectricity, ferroelectricity and magnetic properties in crystals coupled with macroscopic flexibility showcases the immense potential of such crystals for optoelectronic, stress-dissipative and flexible memory applications. However, the limits of mechanical adaptability and their relation to the underlying geometry and energy of the intermolecular interactions remains elusive. The aim of this proposal is to investigate the dependence of intra- and intermolecular interactions within crystals as function of temperature, pressure and uniaxial stress. Within the framework of the project, three model systems viz. a brittle crystal, an elastically and an elasto-plastic crystal shall be studied. At non-ambient temperature, elevated pressure using diamond anvil cells and uniaxial strain, powder and single crystal X-ray and neutron diffraction experiments will be performed to obtain accurate information about positions and displacement parameters of atoms including hydrogens. Systemic analysis of variation of arrangement and energy of intermolecular interactions will be performed as a function of non-ambient temperature and pressure. Successful conclusion of the project will decipher the structure-mechanical response correlations of molecular crystals in general which will be seed to further design of flexible crystals.

Contact:

Dr. Somnath Dey

  AvH Copyright: © AvH

Funding:

Alexander-von-Humboldt Foundation
Title of the project: Structure-mechanical response correlations of elastic molecular crystals as function of temperature, pressure and uniaxial strain
Grant Nr.: Ref 3.5 - 1212718 - IND - HFST-P
Project period: 01.08.2020 - 31.07.2022