A Study on the Dilational Modulus Measurement of Polyacrylic Acid Films at Air-Water Interface by Pendant Bubble Tensiometry.

The dilational modulus (E) of polymer films has been commonly measured using the oscillating ring/bubble/drop methods with an external force, and often without specifying the state of the adsorbed film. This study explores an approach where E was determined from the relaxations of surface tension (ST) and surface area (SA) of natural perturbations, in which ST and SA were monitored using a pendant bubble tensiometer. The E of the adsorbed film of PAA (polyacrylic acid) was evaluated for aqueous solutions at C = 5 × 10 g/cm, [MW = 5, 25, and 250 (kDa)].