2.6. Contact angle measurements (CAM) and energy
characteristics of solid surfaces
The energy characteristics of stainless steel surfaces (S) with
and without an adsorbed biosurfactant layer were determined
by performing contact angles measurements (θ) with the sessile
drop technique (goniometer G40, Kr¨uss, France) and the method
proposed by van Oss et al. [9]. In this approach, the pure liquid
(L) contact angles (θ) can be expressed as: