Curvature Elasticity of Pure and Mixed Surfactant Films

We present here the first theoretical account of the dependence of curvature elastic energies of surfactant layers on area per head group and alkyl carbon number in pure films, and on composition in mixed cases. Treating explicitly the chain conformational statistics, we show that the bending constant can be decreased by an order of magnitude upon halving of the carbon number or upon replacement of as few as one-half of the long chains by the short ones.