Molecular layer deposition process for making organic or organic-inorganic polymers
Ultrathin layers of organic polymers or organic-inorganic hybrid polymers are deposited onto a substrate using molecular layer deposition methods. The process uses vapor phase materials which contain a first functional group and react only monofunctionally at the surface to add a unit to the polymer chain. The vapor phase reactant in addition has a second functional group, which is different from the first functional group, or a blocked, masked or protected functional group, or else has a precursor to such a functional group.
1. A molecular layer deposition process for forming, under appropriate reaction conditions, a layer of an organic polymer or organic-inorganic polymer onto a first hydroxyl-functionalized surface while preventing chain termination and cross-linking, comprising:
reacting a cyclic azasilane comprising 2,2-dimethoxy-1,6-diaza-2-silacyclooctane with a surface hydroxyl on the first hydroxyl-functionalized surface;
allowing a ring of the 2,2-dimethoxy-1,6-diaza-2-silacyclooctane to open and form a silicon-oxygen bond to the first hydroxyl-functionalized surface;
allowing the opened ring of the 2,2-dimethoxy-1,6-diaza-2-silacyclooctane to unfold, thereby leaving a primary amine surface species;
allowing ethylene carbonate to react with the primary amine surface species to generate a urethane linkage to the primary amine surface species, and unfold, thereby forming the layer of the organic polymer or organic-inorganic polymer having a second hydroxyl-functionalized surface.
2. The molecular layer deposition process of claim 1 , wherein the first hydroxyl-functionalized surface and the second hydroxyl-functionalized surface comprise silica.
3. A molecular layer deposition process for forming a layer of an organic polymer or organic-inorganic polymer onto a first hydroxyl-functionalized surface while preventing chain termination, comprising, under appropriate reaction conditions the steps of:
allowing trimethylaluminum in the vapor phase to react with hydroxyl surface groups on the first hydroxyl-functionalized surface, thereby forming an Al—CH 3 surface species;
allowing ethanolamine in the vapor phase to react with the Al—CH 3 surface species, thereby forming an Al—O—CH 2 CH 2 —NH 2 surface species; and
allowing maleic anhydride in the vapor phase to react with the amine, —NH 2 , groups on the Al—O—CH 2 CH 2 —NH 2 surface species, thereby forming the layer of the organic polymer or organic-inorganic polymer having a second hydroxyl-functionalized surface.
4. A molecular layer deposition process for forming a layer of an organic polymer or organic-inorganic polymer onto a first hydroxyl-functionalized surface while preventing chain termination and cross-linking, comprising, under appropriate reaction conditions the steps of:
contacting the first hydroxyl-functionalized surface with 3(1,3-dimethylbutylidene)aminopropyltriethoxysilane (PS) wherein a protecting group hides the —NH 2 functionality;
allowing the PS to form a siloxane linkage to the hydroxylated surface;
contacting the PS surface with water;
allowing the water to react with the imine moiety on the PS, thereby removing the protecting group, releasing 4-methyl-2-pentanone, and forming a surface terminated with primary amine groups;
exposing the surface to an acid chloride or an acid chloride precursor, which bonds to the surface with an amide linkage, the amide linkage producing a nitrobenzyl-protected surface wherein the surface nitrobenzyl-protection group hides an underlying hydroxyl group; and
exposing the surface nitrobenzyl-protection group to ultra-violet light at an appropriate wavelength and for a sufficient period of time to remove the nitrobenzyl-protection group and unmask the underlying hydroxyl group, thereby forming the layer of an organic polymer or organic-inorganic polymer having a second hydroxyl-functionalized surface.