Separating viscoelastic and compressibility contributions in pressure-area isotherm measurements

摘要: Monolayers of surface active molecules or particles play an important role in biological systems as well consumer products. Their properties are controlled by thermodynamics the mechanical interface itself. For insoluble species forming Langmuir monolayers, pressure-area isotherms typically used to characterize thermodynamic state. A trough equipped with a Wilhelmy plate is often for such measurements. However, when interfaces compressed and become more structured, elastic response these can interfere measurement isotherm, even compression speed slow. Recent reports data highly revealed dependence apparent pressures on geometry trough. In present work, this investigated considering adequate constitutive models. Since deformations experiments be large, linearized versions Kelvin-Voigt model do not suffice. We develop framework quasi-linear models choosing suitable non-linear strain tensors, adequately separating shear dilatational effects frame invariant manner. The proposed building blocks describe viscoelastic behavior well. isotherm measurements then shown consequence varying contributions isotropic pressure extra stresses. Using insights, approach obtain intrinsic interfaces. As case study, experimental graphene oxidesheets at air-water evaluate model.