Experimental evidence for a surface concentration-dependent mechanism of formation of hemimicelles in Langmuir monolayers of semi-fluorinated alkanes.

Abstract

We show that formation of surface hemimicelles by a series of molecular semi-fluorinated alkanes CFCH (F8Hm diblocks; = 14, 16, 18, 20) in Langmuir-Blodgett monolayers is not promoted by surface pressure, but depends on the surface area available before transfer, hence on a critical surface concentration. Evidence is provided for the presence of isolated micelles at zero surface pressure (very large molecular area) for certain FnHm diblocks. It is the molecular structure of the diblock that essentially determines the morphology of the hemimicelles, independently of compression conditions.