High refractive index monomers for optical applications
The present invention includes optical coatings containing ultraviolet curable monomers employing a bromine substituted fluorene structure. The fluorene backbone of the monomers of the present invention may also be functionalized with one or more polymerizable or reactive functionalities, and most readily at the 9 position. Compositions of the present invention include the reactive bromosubstituted fluorenes combined with inorganic nanoparticles, particularly nanoparticles with reactive surface modifiers exhibiting polymerizable functionality. Reactive high index nanoparticles such as surface modified zirconia are contemplated.
1. A bromo-substituted fluorene monomer defined by either one of the following formulae:
2. The monomer of claim 1 selected from the group consisting of acrylic acid 3-[9-(3-acryloyloxy-propyl)-2,3,7-tribromo-9H-fluoren-9-yl]-propyl ester, acrylic acid 3-{9-[3-acyloyloxy-propoxy)-propyl]-2,3,7-tribromo-9H-fluoren-9-yl}-propyl ester, 3-[9-(3-acryloyloxy-propyl)-2,7-dibromo-9H-fluoren-9-yl]-propyl ester, and 2-[9-(2-acryloyloxy-ethyl)-2,7-dibromo-9H-fluoren-9-yl]-ethyl ester.
3. A polymerizable composition comprising a bromo-substituted fluorene monomer defined by either one of the following formulae:
4. The composition of claim 3 wherein said bromo substituted fluorene monomer is selected from the group consisting of acrylic acid 3-[9-(3-acryloyloxy-propyl)-2,3,7-tribromo-9H-fluoren-9-yl]-propyl ester, acrylic acid 3-{9-[3-acyloyloxy-propoxy)-propyl]-2,3,7-tribromo-9H-fluoren-9-yl}-propyl ester, 3-[9-(3-acryloyloxy-propyl)-2,7-dibromo-9H-fluoren-9-yl]-propyl ester, and 2-[9-(2-acryloyloxy-ethyl)-2,7-dibromo-9H-fluoren-9-yl]-ethyl ester.