Abstract:
Measurements are described for the force-area curve of stearic acid on pure water at temperatures
of 1.6, 3.0, 5.0, 10.0 and 20.0°C. The Ao values for both solid and liquid films increase with tempera
ture at the same rate, which is greater than for the corresponding cross-sectional areas in the B and
C states of solid stearic acid. There are minima in the compressibilities of both solid and liquid films
around 5°C. Taken together, these data point to an interaction between water molecules and the
stearic acid head groups, related to the water structure as manifested in the temperature of maximum
density of 4°C.
