Universality of breath figures on two-dimensional surfaces: An experimental study

Droplet condensation on surfaces produces patterns, called breath figures. Their evolution into self-similar structures is a classical example of self-organization. It is described by a scaling theory with scaling functions whose universality has recently been challenged by numerical work. Here, we provide thorough experimental testing, where we inspect substrates with vastly different chemical properties, stiffness, and condensation rates. We critically survey the size distributions and the related time-asymptotic scaling of droplet number and surface coverage. In the time-asymptotic regime, they admit a data collapse: the data for all substrates and condensation rates lie on universal scaling functions.