scope:

This test method establishes a procedure for determining the low frequency out of plane dielectric constant and loss tangent of organic free films using a two-fluid method. (Low frequency is defined as less than or equal to 1 MHz in this method.)

The two-fluid method uses a three-terminal guarded electrode cell and allows for capacitance measurements which are independent of sample dimensions, electrode size, and electrode spacing. The two fluids to be used in this procedure are air and 1.0 centistoke silicone fluid.

The change in dielectric constant is the key indicator of moisture uptake and can be used to estimate the mass uptake of water by an organic film. For this reason, the dielectric constant is to be measured on films conditioned at two relative humidity levels and the difference used to estimate a value defined as ''electrical water'' for the sample.