Method for forming a bond between two substrates of a device; device obtainable by the method; a microfluidic device; and use of the device

A method for forming a bond between two substrates of a device, comprising the steps of:

• a. providing a first substrate and a second substrate of a device;
• b. providing a first functionalized polyelectrolyte polymer A comprising a plurality of electrolyte repeating units, wherein at least one of the electrolyte repeating units is a functionalized repeating unit G1 comprising a first functional group comprising a first coupling moiety A1;
• c. providing a second functionalized polyelectrolyte polymer B comprising a plurality of electrolyte repeating units, wherein at least one of the electrolyte repeating units is a functionalized repeating unit G2 comprising a second functional group comprising a second coupling moiety B1;
• wherein the second coupling moiety B1 is selected to be complementary for forming a covalent bond to the first coupling moiety A1 at a temperature below 100° C.;
• d. forming a functionalized surface on an exposed surface of the first substrate having the first functionalized polyelectrolyte polymer A attached to said first substrate;
• e. forming a functionalized surface on an exposed surface of the second substrate having the second functionalized polyelectrolyte polymer B attached to said second substrate;
• f. contacting at least a part of the functionalized surface of the first substrate onto at least a part of the functionalized surface of the second substrate thereby forming a contact area between the first functionalized polyelectrolyte polymer A and the second functionalized polyelectrolyte polymer B;
• and
• g. forming a covalent bond between the first coupling moiety A1 and the second coupling moiety B1 in the contact area between the first substrate and the second substrate for binding the first substrate to the second substrate.

A microfluidic device comprising:

• a. a first substrate comprising a functionalized surface having the first functionalized polyelectrolyte polymer A attached thereon, wherein the first functionalized polyelectrolyte polymer A comprises electrolyte repeating units, wherein at least one of the electrolyte repeating units is a functionalized repeating unit G1 comprising a first functional group comprising a first coupling moiety A1;
• b. a second substrate comprising a functionalized surface having the second functionalized polyelectrolyte polymer B attached thereon, wherein the second functionalize polyelectrolyte polymer B comprises electrolyte repeating units, wherein at least one of the electrolyte repeating units is a functionalized repeating unit G2 comprising a second functional group comprising a second coupling moiety B1;
• wherein the first substrate and a second substrate are bonded to each other at a contact area, wherein the first functionalized polyelectrolyte polymer A contacts the second functionalized polyelectrolyte polymer B;
• and wherein covalent bonds are present between first coupling moieties A1 of the first substrate and second coupling moieties B1 of the second substrate.