Phase-splitting features and polydispersity of droplet/slug flow split in a mini-T-junction: Effect of wall wettability

•Wettability of the T-junction significantly affects both the averaged splitting features of droplet/slug flow and the polydispersity of the split droplets/slugs at the branches.•Critical conditions of high quality even splitting features are suggested.•It draws a more general picture for the phase splitting phenomena in T-junctions with various size.