Computer simulation of a Langmuir trough experiment carried out on a nanoparticulate array

We have used molecular dynamics simulation and thermodynamic arguments to analyze the pressure-area curve resulting from the compression of a monolayer of nanoparticulates at a liquid–vapor interface. The pressure–area isotherm produced by molecular dynamics simulation shows characteristics common to experimental isotherms obtained using the Langmuir-trough technique. The surface pressure exhibits a “knee,” which signals the onset of surface collapse. Visual inspection of the computer simulated monolayers, along with theoretical results from a free energy model of the Langmuir-trough experiment, suggests that the monolayer of particulates buckles under compression. This result is in agreement with recent experimental work on colloids at liquid–liquid interfaces.