Insights into localized manipulation of organogel-related microcrystalline spherulite formation

Abstract The formation processes of microcrystalline spherulitic fiber systems related to bile acid amides were determined to include dominant interface-related aspects, the role of which were studied in terms of potential manipulation and increased control over the overall structure of the networks. The nucleation and growth properties and aggregation of two lithocholyl amide derivatives were studied in several organic solvents using thermomicroscopy, as well as thermal control at macroscopic level. Nucleation/crystallization at interfaces was observed to act as the main route for the formation of microcrystalline fibers/solids in six gelator–solvent systems, in which spherulite formation could be induced at will by localized cooling of the gelation vessel. It was demonstrated in model gelator–solvent systems that the number, locations, and relative sizes of the spherulitic units making up the total fiber network could be manipulated in a way that allows repeating the overall spherulite-based topology of the network in each new heat–cool cycle. The introduced concepts for this class of spherulitic systems may increase their level of applicability through increased control over their macroscopic structure and formation.