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|04 December 2009
Simplification of the landscape under high energy milling of molecular solids exhibiting polymorphismJ. Linol and G. Coquerel
Unité de Croissance Cristalline et de Modélisation Moléculaire, SMS UPRES EA3233 –IRCOF, Université de Rouen F-76821 Mont Saint Aignan Cedex France
Published online: 4 December 2009
Polymorphism is of high occurrence among molecular solids quite often the number of polymorphs exceeds 3 – 4.Several studies have shown that under high energy milling if Tg < Tmilling there is a simplification of the landscape. That is to say for a given milling intensity, whatever the number of polymorphs existing without mechanical stress, a single polymorph corresponds to the steady state. By changing the milling intensity or the composition of the medium (wet milling for instance) a different variety might be accessible. This solid phase can be: the stable thermodynamic form, a metastable thermodynamic form, a dynamic new metastable form, a solvate, a co-crystal, etc. It is only under special conditions of intensity and composition that two polymorphs can co-exist as dual inter-converting steady states.
Key words: High Energy Milling -- polymorphism -- Steady State
© Owned by the authors, published by EDP Sciences 2009