Patterning of liquid crystals using soft-imprint replication of surface alignment patterns
Soft-imprint alignment processes for patterning liquid crystal polymer layers via contact with a reusable alignment template are described herein. An example soft-imprint alignment process includes contacting a liquid crystal polymer layer with a reusable alignment template that has a desired surface alignment pattern such that the liquid crystal molecules of the liquid crystal polymer are aligned to the surface alignment pattern via chemical, steric, or other intermolecular interaction. The patterned liquid crystal polymer layer may then be polymerized and separated from the reusable alignment template. The process can be repeated many times. The reusable alignment template may include a photo-alignment layer that does not comprise surface relief structures that correspond to the surface alignment pattern and a release layer above this photo-alignment layer. A reusable alignment template and methods of fabricating the same are also disclosed.
1. A process for patterning a liquid crystal polymer layer, the processing comprising:
contacting a liquid crystal polymer layer and a reusable alignment template comprising a surface alignment pattern such that liquid crystal molecules of the liquid crystal polymer layer are aligned to the surface alignment pattern of the reusable alignment template primarily via chemical, steric, or other intermolecular interaction;
polymerizing the liquid crystal polymer layer to form a patterned polymerized liquid crystal polymer layer; and
separating the patterned polymerized liquid crystal polymer layer and the reusable alignment template,
wherein the reusable alignment template comprises a photo-alignment layer comprising the surface alignment pattern;
wherein contacting the liquid crystal polymer layer and the reusable alignment template comprises depositing the liquid crystal polymer layer on a surface of the reusable alignment template, wherein depositing the liquid crystal polymer layer further comprises jet depositing the liquid crystal polymer layer; and
wherein the reusable alignment template further comprises a release layer disposed over the photo-alignment layer and a second liquid crystal polymer layer disposed between the photo-alignment layer and the release layer.
2. The process of claim 1 , wherein the surface alignment pattern of the photo-alignment layer does not comprise surface relief structures.
3. The process of claim 1 , wherein polymerizing the liquid crystal polymer layer comprises fixing liquid crystal molecules of the liquid crystal polymer in a desired alignment.
4. The process of claim 1 , wherein separating the patterned polymerized liquid crystal polymer layer and the reusable alignment template comprises delaminating the patterned polymerized liquid crystal polymer layer from the reusable alignment template.
5. The process of claim 4 , wherein the liquid crystal polymer layer or the patterned polymerized liquid crystal polymer layer is secured to a substrate prior to delaminating the patterned polymerized liquid crystal polymer layer from the reusable alignment template.
6. The process of claim 5 , wherein the substrate is optically transmissive.
7. The process of claim 1 , wherein the release layer comprises fluorosilane or polydimethylsiloxane (PDMS).
8. The process of claim 1 , wherein the photo-alignment layer comprises a photoresist.
9. A process for patterning a liquid crystal polymer layer, the process comprising:
depositing a liquid crystal polymer layer on a reusable alignment template comprising a surface alignment pattern such that liquid crystal molecules of the liquid crystal polymer layer are aligned to the surface alignment pattern of the reusable alignment template primarily via chemical, steric, or other intermolecular interaction;
polymerizing the liquid crystal polymer layer to form a patterned polymerized liquid crystal polymer layer; and
delaminating the patterned polymerized liquid crystal polymer layer from the reusable alignment template,
wherein the reusable alignment template comprises a photo-alignment layer comprising the surface alignment pattern;
wherein depositing the liquid crystal polymer layer comprises spin-coating the liquid crystal polymer layer; and
wherein the reusable alignment template further comprises a release layer disposed over the photo-alignment layer and a second liquid crystal polymer layer disposed between the photo-alignment layer and the release layer.
10. The process of claim 9 , wherein the substrate is optically transmissive.
11. The process of claim 9 , wherein the surface alignment pattern of the photo-alignment layer does not comprise surface relief structures.
12. The process of claim 9 , wherein the release layer comprises fluorosilane or polydimethylsiloxane (PDMS).
13. The process of claim 9 , wherein the photo-alignment layer comprises a photoresist.
14. A process for patterning a liquid crystal polymer layer, the processing comprising:
depositing a liquid crystal polymer layer on a surface of a substrate to form a deposited liquid crystal polymer layer;
contacting the deposited liquid crystal polymer layer with a reusable alignment template comprising a surface alignment pattern such that liquid crystal molecules of the deposited liquid crystal polymer layer are aligned to the surface alignment pattern of the reusable alignment template primarily via chemical, steric, or other intermolecular interaction;
polymerizing the deposited liquid crystal polymer layer to form a patterned polymerized liquid crystal polymer layer; and
separating the reusable alignment template and the patterned polymerized liquid crystal polymer layer,
wherein the reusable alignment template comprises a photo-alignment layer comprising the surface alignment pattern; and
wherein the reusable alignment template further comprises a release layer disposed over the photo-alignment layer and a second liquid crystal polymer layer disposed between the photo-alignment layer and the release layer.
15. The process of claim 14 , wherein contacting the deposited liquid crystal polymer layer with the reusable alignment template comprises physically moving the deposited liquid crystal polymer layer and/or the reusable alignment template such that a surface of the deposited liquid crystal polymer layer contacts a surface of the reusable alignment template.
16. The process of claim 15 , wherein separating the patterned polymerized liquid crystal polymer layer and the reusable alignment template comprises physically moving the patterned polymerized liquid crystal polymer layer and the reusable alignment template away from one another.
17. The process of claim 14 , wherein depositing the liquid crystal polymer layer further comprises jet depositing the liquid crystal polymer layer.
18. The process of claim 14 , wherein the surface alignment pattern of the photo-alignment layer does not comprise surface relief structures.
19. The process of claim 14 , wherein the release layer comprises fluorosilane or polydimethylsiloxane (PDMS).
20. The process of claim 14 , wherein the photo-alignment layer comprises a photoresist.