Novel phase diagram of a mixed Langmuir monolayer of octylcyanobiphenyl and stearic acid
Raman Research Institute, Bangalore 560080 India
Corresponding author: firstname.lastname@example.org
Accepted: 26 January 1998
We have studied the phase diagram of a mixed monolayer system of 4-n-octyl-4-cyanobiphenyl (8CB) and stearic acid (SA) at the air-water interface by surface manometry and optical microscopic techniques. We found that in the mixture, a liquid condensed phase (also known as ) was induced which does not occur in the monolayers of the individual components. The induction occurs over a large range of molar concentrations viz. 3% to 95% of SA in 8CB. More interestingly, we observed a phase separation of the liquid expanded (LE) phase (also known as ) into an 8CB-rich LE phase and an SA-rich LE phase for molar concentrations in the range 55% to 95% of SA in 8CB. We also observed a co-existence of three stable phases.
PACS: 68.15.+e – Liquid thin films / 05.70.Fh – Phase transitions: general aspects
© EDP Sciences, 1998