DILATIONAL VISCOELASTICITY OF LIQUID INTERFACES:COMPARISON OF DIFFERENT EXPERIMENTAL CAPILLARY PRESSURE SETUP AND DATA ANALYSIS

Measurement of dynamic interfacial tension and estimation of dilational viscoelasticity parameters is an important request for process designing and optimization in multiphase flow systems, such as in foams and emulsions, extraction, mixing and separation, spraying and particle technology, bubble columns and bioreactors, and microencapsulation in biomedical engineering. However for fast dynamic conditions, crucial for many practical applications, formation and control of interfaces and simultaneously measurement of basic parameters, such as interface contour and capillary pressure, is very difficult and requires special tools. The measurement tools should have a sufficiently high sensitivity, without getting strongly affecting from any types of perturbations. This is why the development of measurement tools like capillary pressure techniques for fast dynamic conditions needs enormous efforts from a theoretical basis and practical application point of view. The basis of this methodology has been described during the last decade and the method has been used for many systems. However for fast dynamic conditions the experimental technique is still under development and needs improvement in hardware, software, experimental protocols and data analysis [1, 2]. The main objective of the presented research is comparison of the performance of two different experimental setups (CPT and ODBA), the corresponding experimental protocols and data analysis. This includes the estimation of the hydrodynamics contribution, compressibility and noise effects on the measured total pressure during growing/oscillating bubble/droplet experiments. References. [1] A. Javadi, J. Krägel, P. Pandolfini, G. Loglio, V.I. Kovalchuk E.V. Aksenenko, F. Ravera, L. Liggieri and R. Miller, Colloids and Surfaces A: 365 (2010) 62-69 [2]F. Ravera G. Loglio, P. Pandolfini, E. Santini, L. Liggieri, Colloids and Surfaces A: 365 (2010) 2-13. Corresponding author: aliyar.javadi@mpikg.mpg.de