If the drop is in an "isolated" condition, that is it is not in contact with any condensed body, its shape is a spehere, regardless of its volume and its surface tension. This condition can be verified under microgravity conditions. However, also in microgravity, residual accelerations affecting the liquid volume, cause distortions of the shape and internal mouvements in the liquid phase.

BUT, if you think of a drop in contact with a solid some additional considerations  are necessary. First of all, if the drop is resting on a solid substrate, "wetting" phenomena take place, and the drop shape can vary from that of a spherical segment ( microgravity) to the one described by the Laplace equation. The drop shape is descibed by the Bond number, which is a function of drop surface tension, drop density and drop volume. HOWEVER, also in this case we cannot say the there is a functional link between drop volume and surface tension.

ON THE CONTRARY, if you are in the "pendant drop" configuaration, the max volume of the drop you can  leave attached  IS a function, inter alia, of drop density and of its surface tension.

Just to add some more info, I remind you that the pendant drop configuration CAN be used to measure the drop surface tension by the DROP WEIGHT method. So, in this case, you can say that the drop volume ( i.e. its weight through itsensity) is used to measure the surface tension.

Just as an example, have a look to the paper:

New drop weight analysis for surface tension determination of liquids

By: Lee, Boon-Beng; Ravindra, Pogaku; Chan, Eng-Seng

COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS Volume: 332 Issue: 2-3 Pages: 112-120 Published: JAN 15 2009

The definitive study on the relation between drop volume, during dripping, and surface tension is the beautiful paper: "Analysis of the drop weight method" by Yildirim,Ozgur E.; Xu,Qi; Basaran,Osman A., Physics of Fluids, volume 17, page 062107/1, 2005. Everything is explained.

Sir,

       Suppose I know the surface tension of water. Also I calculate the drop volume of water and surfactant added water, by counting number of drops dispensing 1 ml of both the liquids. Can I calculate the surface tension of the surfactant added water drom any direct relationship?

The ratio of any two drop volumes is almost equal to the ratio of the corresponding surface tension values.

Article The Effect of Droplet Size on Surface Tension

Dr. Mr Haldar,

The well known paper by Tolman  is not relevant in this case, because drop dimensions can affect their surface tension only at the sub-micrometric scale.

When using the drop weight method with two liquids that differ only for the concentration of the surfactant it is clear that the weight  of the collected drops should be in direct relation to their surface tension. However, the wetting conditions at the syringe tip and the detaching mechanisms could  make this comparison no longer reliable. Moreover, if you measure not the weight of the collected drops, but their volume (you mention  1 ml) the error in the volume measurement is certainly too large.

It may be interesting for you to read also this paper:

Surface tension measurements of refractory liquid metals by the pendant drop

method under ultrahigh vacuum conditions: Extension and comments on Tate’s

law

B. Vinet, J. P. Garandet, and L. Cortella

Journal of Applied Physics 73, 3830 (1993);

Best regards.

Alberto - Thanks for the nice reference ("New drop weight analysis..."). It is a fine update to the paper that I cited & available on open access too. Recommended.

Can I use stalagmometric method for determining surface tension from drop volume?

Yes, that would be fine.

Sir, 

     For calculation from Tate's Law (sigma=m*g/2*pi*r) where r= radius of dripping tip. For radius which diameter should be considered: inside or outside?

If the liquid wets the dripping tip the outside diameter should be used.

Best regards

if i use microsyringe can Iuse the Tate's equation or H-B equation .

Can anyone provide me the pdf version of the paper?

http://onlinelibrary.wiley.com/doi/10.1002/jps.2600610842/abstract