Process for manufacturing a microfluidic device

A process for manufacturing a microfluidic device comprising:

• a) providing a first substrate having a first surface comprising a first flat part and a first concavity and a second substrate having a second surface comprising a second flat part and an optional second concavity, wherein each of the first flat part, the first concavity and the second flat part has surface groups selected from alcohol, aldehyde, carboxylic acid, ether, epoxide, alkene, alkyne, secondary or tertiary carbon atoms, arynes, azides, imines, phosphates, sulfonyl fluorides, N-sulfonylimines, vinylsilyl, quinones, phenones, and
• hydrazones, or a combination thereof;
• b) coating at least one of the first surface and the second surface with a coating composition comprising
• i) a monomer A comprising one moiety represented by CH2═CR1R2 wherein R1 represents H or CH3 and R2 represents —COO— or —CONH—, and a non-ionic hydrophilic moiety;
• ii) a monomer B comprising two or more moieties represented by CH2=CR1R2 wherein R1 represents H or CH3 and R2 represents —COO— or —CONH—, and a non-ionic hydrophilic moiety;
• iii) optionally a photoinitiator;
• iv) optionally a diluent;
• c) evaporating the diluent if present, and forming a liquid coating;
• d) contacting the substrates so as to obtain an assembly in which the first flat part and the second flat part contact each other to define a microfluidic structure between the first and the second surfaces, wherein the microfluidic structure comprises the first concavity and the optional second concavity;
• and
• e) at least partially irradiating the assembly with light having a wavelength between 200 and 800 nm to crosslink the liquid coating to bond the first flat part and the second flat part and obtain a crosslinked coating on at least the first concavity,
• wherein at least one of the first substrate and the second substrate is transparent to said light.