The spreading characteristics of Langmuir monolayers of semi-amphiphilic salts containing the bis(4,5-dimercapto-1,3-dithiole-2-thionato)metallate anion

Monolayers of salts containing dmit anions have been formed at the air/water interface and the influence of spreading time on the pressure/surface area isotherms investigated. The temporal evolution of the isotherms is shown to be related to the dispersion of solid, bulk phase material formed at the air/water interface immediately after spreading. Atomic force microscopy has been used to determine the rate of dispersion by analysing the root mean square (RMS) roughness of Langmuir-Blodgett monolayers deposited after different spreading times. For divalent complexes, changing the central metal atom leads to different dispersion rates, but the initial RMS roughness is similar. Conversely, complexes with the same metal atom but different valencies disperse at the same rate but have very different initial RMS roughnesses.