Methods and device for fast creation of fluid interfaces and use of this device for determination of liquid-liquid and liquid-gas interfacial properties

摘要

Summary of the invention;The invention proposes new methods for fast fresh surface formation of a drop or bubble of a test fluid and a device to realize the new methods to determine the dynamic or equilibrium surface/interfacial tension (ST/IFT) of this liquid. The methods are implemented by means of a single device which is used both for dynamic and equilibrium measurements of the ST/IFT. Depending on the method, the determination of the ST/IFT can be performed either by Axisymmetric Drop Shape Analysis (ADSA) or Capillary Pressure Method (CPM) or both. In addition, with this device the Drop Volume Method and Stopped Jet Method can be realized, which has been modified and improved with the proposed invention in comparison with the known methods. The combination of several methods for creating a fresh surface and of two techniques for determining ST/IFT in a single device allows choosing the most suitable method for a given fluid system considering the system properties and desired time range.;The proposed device consists of the following components:- a capillary tube (5), to which tip a drop/bubble is attached (1) and which is connected to a pressure detector (12) and to an injection module (6), which controls the fluid (gas and/or liquid) in the inner volume;- an optical imaging system, typically comprising illumination source (7) optical lenses (8), and image detection system (9), e.g. video camera and video A/D-converter;- electronics (10) and computer (11) with software to control the device, to analyze drop shapes and pressure signals, if needed, and to determine the ST/IFT.- a glass cuvette (13) with optical windows, used as a container for the outer fluid phase (2).