Fluorinated photopolymer composition and waveguide device
A photosensitive composition having low absorption loss at 1,300-1,610 nm and is suitable for practical waveguide devices. The composition comprises at least one (meth)acrylate prepared from a fluorinated monomer or polymer having minimum two hydroxyl groups, at least one multifunctional non-fluorinated (meth)acrylate and at least one photoinitiator. An optical coating on a variety of substrates is obtained by exposing the photosensitive composition to actinic radiation such as UV light. An optical waveguide device is fabricated by patterning the photosensitive composition on a substrate.
1. A composition comprising,
a) at least one fluorinated (meth)acrylate prepared from a fluorinated monomer or polymer having at least two hydroxyl groups per molecule;
b) at least one non-fluorinated (meth)acrylate, said at least one non-fluorinated (meth)acrylate being soluble in said fluorinated (meth)acrylate, said non-fluorinated (meth)acrylate having at least two (meth)acrylate groups per molecule; and
c) at least one photoinitiator, said photoinitiator being soluble in the fluorinated (meth)acrylate;
wherein said at least one fluorinated (meth)acrylate is prepared from an ethoxylated fluoropolymer having the following formula:
Rf—(—O—(—CH 2 —CH 2 —O) m —H) n
wherein Rf is a fluorinated moiety having a F/H ratio of at least 3:1, m=1-10, and n=2-6.
2. The composition of claim 1 , wherein said at least one fluorinated (meth)acrylate has a number average molecular weight of at least 400.
3. The composition of claim 1 , wherein said at least one non-fluorinated (meth)acrylate has at least 3 (meth)acrylate groups per molecule.
4. The composition of claim 1 wherein the fluorinated (meth)acrylate is prepared from a fluorinated hydroxy-containing monomer or polymer and (meth)acryloyl chloride using a hindered tertiary amine, said amine having at least one tertiary or quaternary carbon atom.
5. The composition of claim 4 wherein the hindered tertiary amine is N,N-diisopropylethylamine.
6. The composition of claim 1 further comprising additives selected from the group consisting of contrast enhancers, UV stabilizers, antioxidants, surfactants, adhesion promoters, and viscosity thickeners.
7. A polymer coating formed by exposing the composition of claim 1 to an actinic radiation.