Polysiloxane formulations and coatings for optoelectronic applications
A crosslinkable composition includes a first silicon-containing resin comprising alkyl groups and alkyl groups and a second silicon-containing resin comprising alkyl groups. The first silicon-containing resin has a weight average molecular weight from 1000 AMU to 10,000 AMU. The second silicon-containing resin has a weight average molecular weight from 900 AMU to 5000 AMU. The composition further includes at least one solvent and at least one heat-activated catalyst.
1. A crosslinkable composition, comprising:
a first polysiloxane resin comprising alkyl groups, wherein from 14% to 100% of the carbon atoms in the first polysiloxane resin are contained in the alkyl groups, the balance of carbon atoms contained in aryl groups, the first polysiloxane resin having a weight average molecular weight from 1000 AMU to 10,000 AMU;
a second polysiloxane resin comprising aryl groups, wherein all of the carbon atoms in the second polysiloxane resin are contained in the aryl groups, the second polysiloxane resin having a weight average molecular weight from 900 AMU to 5000 AMU;
at least one solvent; and
at least one heat-activated catalyst.
2. The crosslinkable composition of claim 1 , further comprising at least one surfactant.
3. The crosslinkable composition of claim 1 , further comprising at least one adhesion promoter.
4. The crosslinkable composition of claim 1 , wherein the first polysiloxane resin comprises methylsiloxane, phenylsiloxane, and dimethyldiethoxysilane, and the second polysiloxane resin comprises phenylsiloxane.
5. The crosslinkable composition of claim 1 , wherein the first polysiloxane resin further comprises a difunctional siloxane.
6. The crosslinkable composition of claim 5 , wherein the difunctional siloxane is dimethyl siloxane.
7. The crosslinkable composition of claim 5 , wherein the difunctional siloxane comprises at least 0.1 mol.% as a percent of the total moles of siloxane in the first polysiloxane resin.
8. The crosslinkable composition of claim 1 , wherein the percentage of carbon atoms contained in alkyl groups ranges from 5% to 12% based on the total number of carbon atoms in the first and second polysiloxane resins.
9. A crosslinked film formed from the crosslinkable composition of claim 1 , wherein the crosslinked film has a thickness of 1.5 μm or greater.
10. The crosslinked film of claim 9 , wherein the crosslinked film has a thickness of 3.0 μm or greater.
11. The crosslinked film of claim 9 , wherein the crosslinked film is cured at a temperature of 350° C. or greater.
12. A device comprising a crosslinked film according to claim 9 , wherein the device is selected from the group consisting of a transistor, a light-emitting diode, a color filter, a photovoltaic cell, a flat-panel display, a curved display, a touch-screen display, an x-ray detector, an active or passive matrix OLED display, an active matrix think film liquid crystal display, an electrophoretic display, a CMOS image sensor, and combinations thereof, and wherein the crosslinked film forms a passivation layer, a planarization layer, a barrier layer, or a combination thereof.
13. A method of forming a crosslinked film, the method comprising:
combining a first polysiloxane resin comprising alkyl groups, a second polysiloxane resin comprising aryl groups, a solvent, and a heat activated catalyst to form a crosslinkable composition, wherein from 14% to 100% of the carbon atoms in the first polysiloxane resin are contained in the alkyl groups, the balance of the carbon atoms contained in aryl groups, the first polysiloxane resin having a weight average molecular weight from 1000 AMU to 10,000 AMU, the second polysiloxane resin having a weight average molecular weight from 900 AMU to 5000 AMU, and all of the carbon atoms in the second polysiloxane resin are contained in the aryl groups;
depositing the composition on a substrate; and
curing the crosslinkable composition at a temperature of 350° C. or greater to form a crosslinked film, wherein the crosslinked film has a thickness of 1.5 μm or greater.
14. The method of claim 13 , wherein the first polysiloxane resin comprises methylsiloxane and phenylsiloxane and the second polysiloxane resin comprises phenylsiloxane.
15. The method of claim 14 , wherein the first polysiloxane resin further comprises dimethyl siloxane.
16. The method of claim 13 , wherein the crosslinked film has a thickness of 3.0 μm or greater.
17. The method of claim 13 , wherein the crosslinked film is cured at a temperature of 350° C. or greater.
18. The method of claim 13 , wherein the crosslinked film is cured at a temperature of 390° C. or greater.
19. The method of claim 13 , wherein the first polysiloxane resin comprises methylsiloxane and phenylsiloxane and the second polysiloxane resin comprises phenylsiloxane, the method further comprising reacting a phenyl triethoxysilane-based polymer having a molecular weight of at least 1000 AMU in a solvent in the presence of a catalyst to form the second polysiloxane resin.
20. The method of claim 19 , wherein the catalyst is a tetraorganoammonium compound.