Formation of Crystalline Hollow Whiskers as Relics of Organic Dissipative Structures

This work presents an original general route to obtain faceted tubular organic crystals (of several tens of micrometers in section) by putting the compound inside a thermal gradient. These hollow whiskers grow spontaneously when the thermal gradient exceeds a certain threshold, the highest temperature being close to the melting point, the lowest temperature being RT. This phenomenon could be explained by heat dissipation and transport of matter thanks to sublimation mechanisms and/or capillarity, i.e. by convective heat transfer. The open system is characterized by energy transport, entropy creation and spontaneous apparition of anisotropy. That is the reason why these hollow whiskers can be considered as relics of dissipative structures (Prigogine, I. Wiley: New York, 1967).