Tunable refractive index polymers
Disclosed is a coating comprising a polymeric layer, wherein the polymeric layer comprises a reaction product of a first monomer comprising two or more aromatic acetylene groups and a second monomer comprising two or more cyclopentadienone groups, or a cured product of the reaction product. The coating may or may not additionally contain a crosslinker and/or a thermal acid generator. Optical thin films made from the coatings exhibit refractive indices that make them useful as interlayers for matching refractive indices between adjacent layers of display devices; thereby improving device output efficiency.
1. A coating comprising a polymeric layer, wherein the polymeric layer comprises a reaction product of a first monomer comprising two or more aromatic acetylene groups and a second monomer comprising two or more cyclopentadienone groups, or a cured product of the reaction product, wherein the first monomer comprising two or more aromatic acetylene groups is
and wherein the coating additionally comprises a crosslinker.
2. The coating according to claim 1 , wherein the second monomer comprising the two or more cyclopentadienone moieties has Formula 3:
wherein: each R 4 is independently H, substituted or unsubstituted C 1-6 alkyl, substituted or unsubstituted C 6-20 aryl, or substituted or unsubstituted C 4-20 heteroaryl; R 5 is substituted or unsubstituted C 6-20 aryl, or substituted or unsubstituted C 4-20 heteroaryl; R 6 is independently substituted or unsubstituted C 1-6 alkyl, substituted or unsubstituted C 6-20 aryl, or substituted or unsubstituted C 4-20 heteroaryl; and Ar 2 is an aromatic moiety.
3. The coating according to claim 2 , wherein Ar 2 has Formula 4:
wherein: Z is the same or different at each occurrence and selected from the group consisting of a single covalent bond, an alkyl group, O, C(O), C(S), CF 2 , and C(CF 3 ) 2 ; q is an integer from 1 to 3; r is an integer from 0 to 2; and Ar 3 is the same or different at each occurrence and is selected from the group consisting of Formula 5 and Formula 6:
wherein: R 7 is the same or different at each occurrence and is selected from the group consisting of halogen, substituted or unsubstituted C 1-6 alkyl, aryl, and aryloxy; c is an integer from 0 to 4; and d and e are the same or different at each occurrence and are each an integer from 0 to 3.
4. The coating according to claim 1 , wherein the crosslinker is a glycoluril compound.
5. The coating according to claim 4 , wherein a weight percentage of the crosslinker in the polymeric layer is between 5% and 20%.
6. The coating according to claim 1 , wherein the polymeric layer comprises the cured product of the reaction product and the cured product of the reaction product is formed by curing the reaction product at a temperature between 200° C. and 300° C.
7. The coating according to claim 6 , wherein the reaction product is cured for a time greater than or equal to 5 minutes.
8. The coating according to claim 1 , wherein the second monomer comprising two or more cyclopentadienone groups is
9. The coating according to claim 8 , wherein the crosslinker is
10. An optical thin film comprising the polymeric layer of claim 1 .
11. A display device comprising the optical thin film of claim 10 .