Synthesis and pH-dependent self-assembly of semifluorinated calix[4]arenes

A new series of highly fluorinated calix[4]arene-based amphiphilic molecules was designed and synthesized. Using the calix[4]arene scaffold, four perfluorinated hyper-hydrophobic groups and four water solubilizing chains were introduced in the same molecule and also segregated in space following the scaffold directionality. Upon solubilization in aqueous solutions, these amphiphilic molecules form microscopic fluorous domains that drive the formation of various self-assembly patterns. We found that the self-assembly of these semifluorinated calix[4]arenes is dependent on external stimuli, such as changes in the polarity of the solvent or pH. As a consequence, by changing the pH of the solutions, it is possible to shift the aggregation pattern of these molecules, by a regular change either in the shape or in the size of the initially formed ordered aggregates. These are examples of the variety of structures and possibilities in nano-engineering offered by fluorous-phase driven molecular recognition.