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Orthogonal Orientation of Chromonic Liquid Crystals by Rubbed Polyamide Films
Author(s) -
Mcguire Aya,
Yi Youngwoo,
Clark Noel A.
Publication year - 2014
Publication title -
chemphyschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.016
H-Index - 140
eISSN - 1439-7641
pISSN - 1439-4235
DOI - 10.1002/cphc.201301040
Subject(s) - rubbing , materials science , birefringence , liquid crystal , polyamide , optical microscope , optics , texture (cosmology) , dichroism , perpendicular , polyester , optoelectronics , composite material , nanotechnology , scanning electron microscope , physics , image (mathematics) , geometry , mathematics , artificial intelligence , computer science
Abstract Chromonic liquid crystals (CLCs) have drawn attention for applications to organic electronics and optical films as well as biological materials. Understanding the alignment mechanism of CLCs is important for those applications. Using a polarized transmission optical microscope, we observe the optical texture, dichroism, and birefringence of CLC films of sunset yellow (SSY) confined by polyamide (nylon) films that are rubbed with a brush. The films align with the stacks of SSY molecules oriented, surprisingly, perpendicular to the rubbing direction. We propose that this alignment is stabilized by molecular interaction between the stretched nylon chains and molecular grooves of the SSY stacks rather than elastic energy of the CLCs due to surface topography induced by the rubbing.