Ion Beam Alignment of Nematic Liquid Crystal on MEH-PPV-Layers

Abstract

Ion Beam alignment of nematic liquid crystal on the surface of poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene] was studied. Our results demonstrate that ion beam treatment provides uniform alignment of LC at the polymer surface, which is characterized by a weak anchoring. Application of polarization microscopy, magneto-optical measurements, Confocal Microscopy and X-ray Photoelectron Spectroscopy, allows us to propose a model of ion beam alignment. Oblique ion bombardment results in an angular anisotropic destruction of side chains and conjugated fragments of the polymer. This results in anisotropic angular distribution of polymer fragments, producing an axis of easy orientation for LC in the direction parallel to the projection of the ion beam.

Keywords:

• Confocal Microscopy
• ion beam alignment
• MEH-PPV
• nematic liquid crystal
• XPS

Acknowledgments

This work is supported by NSF CHE-9613880 and by CRDF grant UK-P1-2598-KV-04. The XPS was funded by a grant from the Keck Foundation and NSF CHE-0113724. Confocal Microscopy is funded through UNM Keck Nanofluidics Laboratory.