Lupane type triterpenes as structuring elements in the monolayers and films of lecithin and fullerene derivatives

Abstract

Using compression and wetting isotherm analysis, it was shown that lupane triterpenes (betulinol, betulinol diacetate, betulinic acid) change crucially the state of monolayers and films of C60 fullerene, nitroxide malonate C60 methanofullerene, and lecithin and also the films of their mixtures at the water—air interface. The structuring action of triterpenes in the presence of lecithin and C60 fullerene at high triterpene contents in the film gives rise to uniaxially oriented films similar to thin films of triterpenes (atomic force microscopy data). The formation of mixed bis-nitroxide malonate methanofullerene—triterpene films with excess of the latter affords structures shaped like crater-like bowls.