Jet ejection device

A microfluidic device (1) for jet ejection, wherein the microfluidic device (1) comprises a hosting chamber (100) defined by a chamber wall (110), wherein:

• the hosting chamber (100) is configured to host a liquid (10), wherein along a device axis of elongation (AD) the hosting chamber (100) has a chamber length (LC) defined by a first chamber end (101) and a second chamber end (102), wherein the first chamber end (101) comprises a first chamber opening (1011) for jet ejection from the hosting chamber (100);
• the chamber wall (110) comprises a pattern (300) of a first surface material (111) and a second surface material (112), wherein the first surface material (111) has an equilibrium contact angle θ1>90° for the liquid (10), and wherein the second surface material (112) has an equilibrium contact angle θ2 for the liquid (10), wherein θ1−θ2≥20°;
• the pattern (300) comprises a patch (200), wherein the patch has a patch boundary (205), and wherein (a) the patch (200) comprises one of the first surface material (111) and the second surface material (112), and wherein (b) at least 50% of the patch boundary (205) contacts the other of the first surface material (111) and the second surface material (112);
• the chamber wall (110) has a wall surface area (SW), wherein the patch (200) has a patch surface area (SP), wherein 10−4≤SP/SW≤2*10−1;
• and
• in a cross-section perpendicular to the device axis of elongation (AD) the hosting chamber (100) has a perimeter (115) with a chamber perimeter length PC, wherein the patch (200) covers a patch perimeter length PP along the perimeter (115), wherein PP is selected from the range of 0.01*PC-0.5*PC.