The effect of contact angle hysteresis on droplet coalescence and mixing

► Teflon surface, consistent advancing contact angle, varied contact angle hysteresis. ► Droplet coalescence on minimal hysteresis mimic air-based droplet coalescence. ► Droplet coalescence falls into three distinct regimes. ► Increased hysteresis dampens droplet coalescence dynamics. ► Droplet mixing is enhanced on low hysteresis surfaces.