SINTERFACE  News, Exhibitions and Workshops

News

Software for Modelling

New Developments

A new generation of bubble pressure tensiometers, including BPA-2P and BPA-2S, as follow up developments of the excellent predecessors BPA-1P and BPA-1S, will be available soon. Due to its robust and compact construction the old two instruments have been particularly suitable for various applications. The new instruments will provide more modern features, such as Ethernet connection. The mechanical parts, in particular the automatic immersion of the capillary into the liquid, are significantly improved.

The BPA-2P is again portable and is equipped such that it can work as "stand-alone" instrument, having a respective large memory on board. Via special software it can be used for on-line process control, using the surface tension as control parameter.

The development of the new high end bubble pressure tensiometer BPA-2S provides again the shortest adsorption times available worldwide. To reach these ultra short adsorption times of less than one millisecond, again the principle of Fainerman is applied. This principle allows determining accurately the deadtime of bubble formation at highest bubble frequencies. The instrument is dedicated to users in science and development departments particularly interested in extremely short adsorption times, such as foaming or coating processes. The new hardware is based on very precise pressure and gas flow sensors and utilises a new principle for bubble time detections.

The interfacial tension between two immiscible liquids at shorter adsorption times, or for systems of small density contrast, can be measured by none of the standard techniques. The only way for such studies is the direct measurement of the capillary pressure in the inner drop phase. The module DPA-1 developed by SINTERFACE works as additional module for the work horse PAT-1. Shortest available adsorption times are of the order of 100 ms and even less.

The ODBA-1 is an advanced version of the DPA-1 that provides the experimental option of measuring oscillating drops and bubbles at frequencies from about 1 Hz up to 100 Hz, depending on the size of the used capillary, i.e. of the oscillating drop. With such experiments the dilational elasticity and viscosity can be measured in a frequency interval complementary to that available by slow oscillations of drops or bubbles in shape tensiometry. In this way, we can provide instrumentation for relaxation experiments in a frequency range between very slow (f < 0.01 Hz) to high oscillations (> 100 Hz).

A unique new tool provided by SINTERFACE Technologies is the Drop and Bubble Micro Manipulation DBMM-1. This instrument allows studies of direct interaction between two drops or bubbles, or even between a drop and a bubble. It can be coupled with a fast video technique in order to quantify processes like drop coalescence or film rupture.

Note, DPA-1, ODBA-1 and DBMM-1 will be available very soon as stand-alone units.

Workshops

4^th User Seminar 2D/3D Rheology

Anton Paar Germany GmbH (Ostfildern, www.anton-paar.com), LUM (Berlin) and SINTERFACE Technologies (Berlin) organised a new type of user seminars, dedicated to the rheology of structured bulk phases and two-dimensional interfacial layers, in relation to the stability of suspersions and emulsions.

The forth 2D/3D rheology seminar is scheduled for May 2011 in Potsdam. Information can be downloaded here.