Anomalous behaviour of droplet coalescence in a two-dimensional complex system

Coalescence of myristic acid droplets on water surface is found to exhibit anomalous behaviour such as simultaneous increase of mean droplet size and droplet number with time at low surface pressure. The existing theories and models can describe droplet evolution at high surface pressure but fail to explain this anomaly at low surface pressure. We propose a more general model for coalescence that reproduces the anomaly at low surface pressure and agrees with other models at high surface pressure. Our model considers microscopic resolution, nucleation of droplets and desorption of droplets in addition to pure coalescence and can be applied to a wide variety of systems.