FTIR study of E7 liquid crystals confined to perfluorinated carboxylic acid treated cylindrical cavities of Anodisc membranes

  • Ha, Ki-Ryong (Dept. of Chemical Engineering, Keimyung University) ;
  • Ahn, Hee-Jun (Dept. of Chemical Engineering, Keimyung University) ;
  • Yoon, Sung-Kyoun (Dept. of Chemical Engineering, Keimyung University) ;
  • Lee, Dong-Ho (Dept. of Polymer Science, Kyungpook National Universitry) ;
  • West, John L. (Liquid Crystal Institute, Kent State University)
  • Published : 2004.08.23

Abstract

Orientation of E7 liquid crystals(LCs) confined to 200 nm-diameter cylindrical cavities of Anodisc membranes are investigated by FTIR dichroism techniques. The cavity walls of the confining pores are chemically modified with different perfluorinated carboxylic acids (PCA, $C_nF_{2n+1}$COOH, n=3, 4, 5, 6). From the FTIR spectra of PCA treated alumina Anodsic membranes, we found the salt formation between -COOH group of PCA and Anodisc membrane. From the FTIR spectra of LC filled Anodisc membranes, we found abrupt alignment direction change of LC molecules between n=4 and 5 for 1 mM PCA treated Anodisc membranes, from parallel to perpendicular direction to the cavity walls. But 5mM PCA treated Anodisc membranes, alignment direction of LC molecules changed between n=3 and n=4, from parallel to perpendicular direction.

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