The present invention relates to a method, comprising: providing a microfluidic system comprising one or more channels (25,28,29); providing within said one or more channels (25,28,29) a first fluidic stream and a second fluidic stream, at least one of which comprises droplets that have an average diameter of less than about 450 microns and that are highly monodisperse; and applying an electric field (40) simultaneously to at least a portion of the first fluidic stream and a portion of the second fluidic stream such that said portions coalesce.