Optical films comprising fluorenol (meth)acrylate monomer

1. An optical film comprising a polymerized microstructured surface wherein the polymerized microstructured surface comprises the reaction product of a polymerizable resin composition comprising at least one aromatic monomer or oligomer having at least two polymerizable (meth)acrylate groups and at least one fluorenol (meth)acrylate monomer having the general structure:

wherein

R is independently a substituent selected from halogen, aryl, or a C 2 to C 12 alkyl group;

t ranges from 0 to 4;

L is a C 2 to C 12 alkyl optionally substituted with hydroxyl;

n ranges from 1 to 10; and

R1 is H or CH 3 .

2. The optical film of claim 1 wherein the polymerizable resin composition comprises at least 5 wt-% of the fluorenol (meth)acrylate monomer.

3. The optical film of claim 1 wherein the polymerizable resin composition comprises up to 50 wt-% of the fluorenol (meth)acrylate monomer.

4. The optical film of claim 1 wherein the polymerizable resin comprises 25 wt-% to 50 wt-% of the aromatic monomer or oligomer having at least two polymerizable (meth)acrylate groups.

5. The optical film of claim 1 wherein the aromatic monomer or oligomer having at least two polymerizable (meth)acrylate groups comprise at least two aromatic rings.

6. The optical film of claim 1 wherein the aromatic monomer or oligomer having at least two polymerizable (meth)acrylate groups has a molecular weight of at least 350 g/mole.

7. The optical film of claim 1 wherein the aromatic monomer or oligomer has the formula

wherein R1 is independently hydrogen or methyl,

Z is independently —C(CH 3 ) 2 —, —CH 2 —, —C(O)—, —S—, —S(O)—, or —S(O) 2 —,

Q is independently O or S,

L is independently a C 2 -C 6 alkyl group optionally substituted with one or more hydroxy groups,

and n ranges from 0 to 10.

8. The optical film of claim 1 wherein the aromatic monomer or oligomer has the formula

wherein each R1 is independently H or methyl;

each R2 is independently Br;

m ranges from 0 to 4;

each Q is independently O or S;

n ranges from 0 to 10;

L is independently a C2 to C12 alkyl group optionally substituted with one or more hydroxyl groups;

z is an aromatic ring; and

t is independently 0 or 1.

9. The optical film of claim 1 wherein the fluorenol (meth)acrylate monomer is

10. The optical film of claim 1 wherein polymerizable composition has a refractive index of at least 1.54.

11. The optical film of claim 1 wherein the polymerizable resin composition comprises less than 1 wt-% total of chlorine, bromine, or mixtures thereof.

12. The optical film of claim 1 wherein the polymerizable resin composition comprises less that 1 wt-% total of chlorine, bromine, fluorine and iodine.

13. The optical film of claim 1 wherein the optical film is a brightness enhancing film having a single sheet gain of at least 1.59.