Observation by atomic force microscopy of calix[n]arene thin films and their thermal rearrangement

Vapor deposited thin films of various calix[n]arenes have been investigated by contact mode atomic force microscopy. Two classes of thin films have been defined. For para-H-calix-4-arene, para-H-calix-6-arene, and para-iso-propyl-calix-4-arene pre-organized structures are observed on deposition. For paraiso-propyl-calix-6-arene, para-tert-butyl-calix-4-arene, para-tert-butyl-calix-6-arene, para-tert-butyl-calix-8-arene glassy unordered systems are obtained on deposition. Annealing of para-iso-propyl-calix-6-arene, para-tert-butyl-calix-4-arene, para-tert-butyl-calix-6-arene at 100 degrees C leads to crystallization either directly from the glass or by migration of nano-crystallites to form microstructures. (C) 1999 Elsevier Science Ltd.