64
Pendant drop shape analysis
The shape of a drop hanging from a syringe tip is determined from the balance of forces that include the
surface tension of that liquid. The surface or interfacial tension at the liquid interface can be related to the
drop shape through this equation.
Where = surface tension
= shape factor
= difference in density between fluids at interface
g = gravitational constant
R0 = radius of drop curvature at apex
The shape factor can be defined through the Young-Laplace equation expressed through 3
dimensionless first order equations as shown in the figure below.
Figure 6.3.
The shape factor is calculated with a Young-Laplace equation.
Modern computational methods using iterative approximations allow solution of the Young-Laplace
equation for β to be performed. Thus for any pendant drop where the densities of the two fluids in contact
are known, the surface tension may be measured based on the Young-Laplace equation.
Summary of Contents for Theta
Page 1: ...Theta User manual OneAttension Optical Tensiometer Revision 1 0...
Page 3: ...6 3 Theory of surface free energy 65 7 TECHNICAL SPECIFICATIONS 70 8 CONTACT INFORMATION 71...
Page 41: ...38 Figure 4 15 Device controls and recipe sheet parameters for multiliquid dispenser...
Page 54: ...51 Figure 4 30 Analysis tab of the PD 200 experiment Figure 4 31 Calculated results...
