Using Pressure Sensors as a Surface Tensiometer?

[gary_feesher]

Hi,

I was wondering if it may be possible to use two piezoresistive pressure sensors to measure the surface tension of a solution?

In short, I am trying to figure out the feasibility of building out a low-cost surface tensiometer, so that I don't need something like the SensaDyne Surface Tensiometer. The Surface Tensiometer uses two orifices which bubble into the liquid and the differential pressure value of the formed bubbles is measured.

Can anyone think of a method to perform surface tensiometry using absolute pressure sensors, say like the LPS333 from STMicro?

Thanks for any feedback!

 

[BradtheRad]

Surface tension is so delicate that I think it must be difficult to measure. I recall easy ways for us to observe it:

* needle (or 2-edge razor blade) rests on top of water
* water level in a full glass bulges higher than the rim of the glass
* water forms drops as small stream falls from faucet,
* water drops become spherical
* insects called water striders skate on water surface.

The springy quality of surface tension is what needs to be detected.
A sensor needs to be delicate so it can measure the weak springy force.
Its sensing method needs to ignore viscosity of liquid.

If you make your own, its results should be an objective measurement (if possible). It sounds more professional if you state a number of units, rather than saying 'surface supported 4 razor blades before they all sank.'