Proceedings of the Polymer Society of Korea Conference (한국고분자학회:학술대회논문집)

The Polymer Society of Korea (한국고분자학회)
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Unusual Alignment of Liquid Crystals on Rubbed Films of Polyimides with Fluorenyl Side Groups

  • Hahm, Suk-Gyu (Polymer Research Institute, Department of Chemistry, National Research Lab for Polymer Synthesis & Physics, Center for Integrated Molecular Systems, BK School of Molecular Science) ;
  • Lee, Taek-Joon (Polymer Research Institute, Department of Chemistry, National Research Lab for Polymer Synthesis & Physics, Center for Integrated Molecular Systems, BK School of Molecular Science) ;
  • Chang, Tai-Hyun (Polymer Research Institute, Department of Chemistry, National Research Lab for Polymer Synthesis & Physics, Center for Integrated Molecular Systems, BK School of Molecular Science) ;
  • Jung, Jin-Chul (Polymer Research Institute, Department of Materials Science & Engineering, Pohang University of Science & Technology (Postech)) ;
  • Zin, Wang-Cheol (Polymer Research Institute, Department of Materials Science & Engineering, Pohang University of Science & Technology (Postech)) ;
  • Ree, Moon-Hor (Polymer Research Institute, Department of Materials Science & Engineering, Pohang University of Science & Technology (Postech))
  • Published : 2006.10.13
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Abstract

In the present study, we synthesized CBDA-FDA and its analogue, poly(4,4' -(9,9-fluorenyl)diphenylene pyromellitimide) (PMDA-FDA), and then investigated quantitatively the orientational distributions of the polymer chain segments in the surfaces of their films by using linearly polarized Fourier transform infrared (FTIR) spectroscopy and optical retardation analysis. We also examined the films' surface topographies using high spatial resolution atomic force microscopy (AFM). Further, rubbed films were used to assemble antiparallel and $90^{\circ}-twisted$ nematic (TN) LC cells, and the alignment behaviors, pretilt angles and anchoring energies of the LC molecules in the cells were determined. The films were found to have very interesting surface morphologies and LC alignment behaviors, which have not previously been reported. The observed LC alignments, pretilt angles and anchoring energies are discussed by taking into account the interactions of the LC molecules with the oriented polymer chain segments and the surface morphologies.

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