Thermodynamics of 4,4'-stilbenedicarboxylic acid monolayer self-assembly at the nonanoic acid-graphite interface.

A direct calorimetric measurement of the overall enthalpy change associated with self-assembly of organic monolayers at the liquid-solid interface is for most systems of interest practically impossible. In previous work we proposed an adapted Born-Haber cycle for an indirect assessment of the overall enthalpy change by using terephthalic acid monolayers at the nonanoic acid-graphite interface as a model system. To this end, the sublimation enthalpy, dissolution enthalpy, the monolayer binding enthalpy in vacuum, and a dewetting enthalpy are combined to yield the total enthalpy change. In the present study the Born-Haber cycle is applied to 4,4'-stilbenedicarboxylic acid monolayers. A detailed comparison of these two aromatic dicarboxylic acids is used to evaluate and quantify the contribution of the organic backbone for stabilization of the monolayer at the nonanoic acid-graphite interface.