Polymorphism Studies of Solid N-p-(Ethoxybenzylidene)-p′-Propylaniline

Abstract

Ethoxybenzylidene-propylaniline (EBPA) was studied using polarizing microscopy and differential scanning calorimetry (DSC) in the temperarure range 100 K–380 K with various heating and cooling rates (from 0.1 deg/min to 200 deg//min). The metastable solid crystal phase was discovered. It is formed rapidly on cooling of nematic phase and transforms spontaneously to stable crystal phase. But can be also frozen or separately melted. The rich polymorphism of isomeric to EBPA MBBA compound is also discussed proving the importance of terminal groups in the formation of different polymorphs.

Key Words:

• liquid crystal polymorphism
• polarizing microscopy
• DSC
• metastable phase