Microfabricated devices with coated or modified surface and method of making same
A microfabricated device or component thereof, such as microfluidics or nanofluidics device having a uniform non-wetting or non-absorbing polymeric coating or surface modification formed on a surface thereof by ionization or activation technology such as plasma processing, to produce a surface energy of less than 15 mNm −1 . The treatment enhances the free-flowing properties of a liquid through the device during use.
1. A microfluidic device comprising:
at least one chamber or tunnel or channel for the containment or flow of at least one fluid, said chamber or tunnel or channel having at least one dimension less than 1 mm and said chamber or tunnel or channel defining one or more surfaces for the containment or flow of the fluid, wherein the entire surfaces of the microfluidic device which, in use, would come into contact with the fluid are provided with a uniform non-wetting or non-absorbing polymeric coating or surface modification formed by plasma processing, and wherein the entire surfaces of the microfluidic device which, in use, would come into contact with the fluid have a surface energy value of less than 15 mNm −1 .
2. The microfluidic device according to claim 1 wherein the coating or surface modification comprises a non-wetting or non-absorbing polymer formed by plasma polymerization of a monomeric compound, and wherein the surface of the device or an element, component or sub-assembly thereof is exposed to the plasma for a sufficient period of time for a uniform layer of the polymer to form on the surface.
3. The microfluidic device according to claim 2 wherein the monomeric compound is a compound of formula (I):
where R 1 , R 2 and R 3 are independently selected from hydrogen, alkyl, haloalkyl or aryl optionally substituted by halo; and R 4 is a group —X—R 5 where R 5 is an alkyl or haloalkyl group and X is a bond; a group of formula —C(O)O—, a group of formula —C(O)O(CH 2 ) n Y— where n is an integer of 1 to 10 and Y is a sulphonamide group; or a group —(O) p R 6 (O) q (CH 2 ) t — where R 6 is aryl optionally substituted by halo, p is 0 or 1, q is 0 or 1 and t is 0 or an integer of 1 to 10, provided that where q is 1, t is other than 0.
4. The microfluidic device according to claim 3 wherein the compound of formula (I) is a compound of formula (II):
CH 2 ═CH—R 5 (II)
where R 5 is an alkyl or haloalkyl group, or a compound of formula (III):
CH 2 ═CR 7 C(O)O(CH 2 ) n R 5 (III)
where n is an integer of 1 to 10 and R 5 is an alkyl or haloalkyl group and R 7 is hydrogen, C 1-10 alkyl, or C 1-10 haloalkyl.
5. The microfluidic device according to claim 4 wherein the compound of formula (I) is a compound of formula (III).
6. The microfluidic device according to claim 5 wherein the compound of formula (III) is a compound of formula (IV):
where R 7 is hydrogen, C 1-10 alkyl, or C 1-10 haloalkyl, and x is an integer of 1 to 9.
7. The microfluidic device according to claim 6 wherein the compound of formula (IV) is 1H,1H,2H,2H-heptadecafluorodecylacrylate.
8. The microfluidic device according to claim 2 wherein the monomeric compound is a compound of formula (V):
where R 8 , R 9 , R 10 , R 11 , R 12 , and R 13 are all independently selected from hydrogen, halo, alkyl, haloalkyl or aryl optionally substituted by halo; and Z is a bridging group.
9. The microfluidic device according to claim 2 wherein the monomeric compound is a compound of formula (VII):
where R 16 , R 17 , R 18 , R 19 and R 20 are independently selected from hydrogen, halogen, alkyl, haloalkyl or aryl optionally substituted by halo; and R 21 is a group X—R 22 where R 22 is an alkyl or haloalkyl group and X is a bond; a group of formula —C(O)O(CH 2 ) x Y— where x is an integer of 1 to 10 and Y is a bond or a sulphonamide group; or a group —(O) p R 23 (O) s (CH 2 ) t — where R 23 is aryl optionally substituted by halo, p is 0 or 1, s is 0 or 1 and t is 0 or an integer of 1 to 10, provided that where s is 1, t is other than 0.
10. The microfluidic device according to claim 2 wherein the monomeric compound is a compound of formula (VIII):
R 24 —C≡C—X 1 —R 25 (VIII)
where R 24 is hydrogen, alkyl, cycloalkyl, haloalkyl or aryl optionally substituted by halo;
X 1 is a bond or a bridging group; and R 25 is an alkyl, cycloalkyl or aryl group optionally substituted by halogen.
11. The microfluidic device according to claim 1 , wherein the surfaces of the chambers, tunnels or channels have an ultra low surface energy less that 12 mNm −1 .
12. The microfluidic device according to claim 1 , wherein the surfaces of the chambers, tunnels or channels have an ultra low surface energy in the range of 8 to 10 mNm −1 .
13. The microfluidic device according to claim 11 , wherein the surfaces of the chambers, tunnels or channels have an ultra low surface energy in the range of 8 to 10 mNm −1 .
14. The microfluidic device according to claim 1 , wherein the entire surface of the microfluidic device is provided with the uniform non-wetting polymeric coating or surface modification.
15. The microfluidic device according to claim 11 , wherein the entire surface of the microfluidic device is provided with the uniform non-wetting polymeric coating or surface modification.
16. The microfluidic device according to claim 12 , wherein the entire surface of the microfluidic device is provided with the uniform non-wetting polymeric coating or surface modification.
17. The microfluidic device according to claim 13 , wherein the entire surface of the microfluidic device is provided with the uniform non-wetting polymeric coating or surface modification.
18. The microfluidic device according to claim 1 , wherein the chamber, tunnel or channel has at least one dimension less than 100 nanometers.
19. The microfluidic device according to claim 11 , wherein the chamber, tunnel or channel has at least one dimension less than 100 nanometers.
20. The microfluidic device according to claim 12 , wherein the chamber, tunnel or channel has at least one dimension less than 100 nanometers.