Oxidation state investigation concerning liquid crystal alignment on polydimethylsiloxane layer by ion beam irradiation

Abstract

This is a study of ion beam (IB)-irradiated polydimethylsiloxane (PDMS) layer-induced liquid crystal (LC) effects and electro-optical (EO) properties with varying IB incident angles. Depending on the incident angle, the homogeneously aligned LC on the PDMS layer via IB irradiation was embodied with LC alignment capability and performance. Based on X-ray photoelectron spectroscopic (XPS) analysis, the intensity of O–Si as a function of incident angle shows oxidation of the IB-treated PDMS surface. It revealed that van der Waals forces generated by delocalised electrons on the PDMS surface were attributed to LC alignment by selective destructions of the Si–C bonding in the direction of IB irradiation. EO characteristics comparable with rubbed polyimide were also achieved.

Keywords:

• electro-optic properties
• liquid crystal alignment
• polydimethylsiloxane
• X-ray photoelectron spectroscopy

Acknowledgement

This research was supported by the MKE (The Ministry of Knowledge Economy), Korea, under the ITRC (Information Technology Research Center) support program supervised by the NIPA (National IT Industry Promotion Agency) (NIPA-2011-C1090-1111-0002)