Fyzikální ústav Akademie věd ČR

Seminář Úterý, 23.02.2016 13:00 - 14:00

Přednášející: Yousra Tahri (Universite de Lyon, Universite Claude Bernard Lyon 1, France)
Místo: Library of the Institute of Physics, Cukrovarnicka 10, Praha 6
Jazyk: anglicky
Pořadatelé: Oddělení optických materiálů

When a substance can exist in more than one crystalline state it is said to exhibit polymorphism. Two polymorphs have the same chemical composition but different physical and chemical properties (solubility, compressibility, melting point…) and then are considered as two different materials. Thus it is crucial to fully characterize all the polymorphs of a compound to avoid any transformation during manufacturing or storage. This work deals with the study of the polymorphism of L-Glutamic acid (LGlu) which can crystallize in two known monotropic polymorphs: the stable form β with needle like shape and the metastable form α with prismatic shape. Two experimental devices were used. Cooling crystallizations in water were performed in both a stirred double jacketed vessel of 2 L and a non-agitated thermostated cell of 4 mL. The crystallization was monitored in situ by a video probe in stirred conditions and by a microscope in stagnant conditions. Effect of temperature and supersaturation on the polymorphism of LGlu was investigated in stirred and stagnant conditions. Then the results were compared.