Advances in drop and bubble profile analysis tensiometry

Profile analysis tensiometry (PAT) with drops and bubbles is a successful methodology to characterize liquid-fluid interfaces. Questions about the most suitable size of drops and bubbles have been solved now on the basis of dimensionless numbers. The consideration of the standard deviation between measured and calculated liquid profiles as sensitive measure for the applicability of PAT provides a tool for its correct use. For solutions of highly surface-active compounds, bulk depletion effects can cause systematic errors in the analysis of adsorption kinetics, equations of state, and the visco-elastic interfacial behavior of liquid adsorption layers. Great progress has been made in measurements of interfacial dilational rheology with large amplitude perturbations providing additional information about structure and dynamics of complex adsorption layers. Also, first attempts are successfully made to use artificial intelligence (AI) to enhance the efficiency of PAT applications. Thus, PAT has established a solid position in surface science.