Related Experiment Video
Updated: Jun 12, 2026

Orientational Transition in a Liquid Crystal Triggered by the Thermodynamic Growth of Interfacial Wetting Sheets
Published on: May 15, 2017
Structural and dynamic heterogenization and phase transition in plastic crystal phase: Taking a representative
1Department of Chemistry, Graduate School of Science, Chiba University.
None:
A plastic crystal (PC) has a crystalline phase characterized by disordered molecular (or ionic) orientations while maintaining a regular lattice of their positions. It is in a molten state from the perspective of orientation, while in a crystalline state from the perspective of position. Recent studies have reported heterogeneous dynamics within the PC phase, regardless of whether it is a molecular PC (MPC) or an ionic PC (IPC). By measuring the spin-lattice relaxation time (T1) and the spin-spin relaxation time (T2) using low-frequency NMR, it is possible to separately observe the reorientation motion of molecules (or ions) from T1 and their translational motion from T2. We present the results of relaxation time measurements using an MPC and an IPC samples. The heterogeneous dynamics is attributed to the existence of static heterogeneous regions in the PC phase: the core region and the surrounding region enveloping it. We demonstrate that molecules (or ions) within each region exhibit distinct translational motion behaviors, with the surrounding region particularly leading to a pre-melting phenomenon. This heterogenization may be described "a phase separation in solid phase".
Related Concept Videos
Polymer Classification: Crystallinity
Crystalline domains are the regions where polymer chains are aligned in an orderly manner and held together in proximity by intermolecular forces. For example, chains in the crystalline domains of polyethylene and nylon are bound together by van der Waals...
Molecular and Ionic Solids
Molecular Solids
Molecular crystalline solids, such as ice, sucrose (table sugar), and iodine, are solids that are composed of neutral molecules as their constituent units. These molecules are held together by weak intermolecular forces such as London dispersion forces, dipole-dipole interactions, or hydrogen bonds, which...
Phase Transitions: Melting and Freezing
Classification and Mechanical Properties of Synthetic Polymers
Phase Transitions
Phase Transitions

