The surface modification characteristics of liquid crystal (LC) alignment layers irradiated with various argon (Ar) ion beam (IB) energies were investigated as a substitute for rubbing technology. Various pretilt angles were created on the IB-irradiated polyimide (PI) surfaces after IB irradiation, but the Ar ions did not alter the morphology on the PI surface, indicating that the pretilt angle was not due to microgrooves. The chemical bonding states of the IB-irradiated PI surfaces were analyzed in detail by x-ray photoelectron spectroscopy to verify the compositional behavior for the LC alignment. Chemical structure analysis showed that the alignment ability of LCs was due to the preferential reorientation of the carbon network due to the breaking of C=O double bonds in the imide ring parallel to the incident IB direction. The potential of applying nonrubbing technology to display devices was further supported by the superior electro-optical characteristics compared to rubbed PI.
Bibliographical noteFunding Information:
This research was supported by the Ministry of Knowledge Economy (MKE), Korea under the Information Technology Research Center (ITRC) Support Program supervised by the Institute of Information Technology Advancement (IITA) (Grant No. IITA-2008-C1090-0801-0018).
All Science Journal Classification (ASJC) codes
- Physics and Astronomy(all)