A Study of the Properties of Tri-n-octylphosphine Oxide (TOPO) Monolayers at the Air/Water Interface

Tri-n-octylphosphine oxide (TOPO) was found to be capable of Langmuir monolayer formation at the air/water interface. Surface pressure-area ( -A) isotherms obtained at different experimental conditions (barrier speed, number of deposited molecules, temperature and presence of metal ions in the aqueous subphase), compression modulus (Cs 1) values andBAMimages have been analyzed. The stability of TOPO monolayers has also been thoroughly examined. The obtained results indicate a liquid state of TOPO monolayers independently of subphase temperature or ionic strength. Such experimental conditions as the barrier speed or the number of deposited molecules were found to have no influence on the shape and position of the isotherms. Moreover, the performed experiments proved a high stability of monolayers from TOPO at the air/water interface.