Multiple interactions between microfluidic droplets and on-chip pneumatic valves

Microfluidic droplet arrays potentially allow to carry out assays involving complex workflows at the single-cell level. In recent developments [e.g. (Jeong et al. in Lab Chip 16:1698, 2016)], each of array can be addressed individually thanks on-chip pneumatic valves. this experimental and theoretical work, we investigate multiple interaction regimes between one or several droplets a valve. particular, two main trapping modes are characterized, with very distinct flow features. We quantify huge increase hydrodynamic resistance induced by droplet/valve interaction. Finally, rationalize transitions trapped non-trapped through generic model balance capillary, elastic forces.