MOLECULAR DYNAMICS AND PHASE TRANSFORMATIONS: FROM SOFT MATTER TO CRYSTALLINE SOLIDS

In this lecture several case studies will be shown where phase transitions or phase transformations have been investigated by solid-state NMR techniques by looking at the dynamic properties of the systems at a molecular level. To this aim, different properties of 1H, 2H and 13C nuclei have been exploited, such as lineshapes and linewidths, spin-lattice relaxation times in the laboratory (measured either by conventional methods or by fast-field cycling) and in the rotating frame, spin-spin relaxation times. In particular the following studies will be described: i) phase transitions in glass formers exhibiting a rich polymorphism, including several plastic crystalline phases; ii) phase transformations between hydrated and anhydrous forms of crystalline drugs; iii) glass transition and cold crystallization in polymeric materials; iv) phase transformations induced by temperature or guest molecules in complex self-assembled systems of biological interest.