Characterization of Vertical Alignment Film by X-Ray Reflectivity

Depth profile of mass density of vertical alignment film was investigated by X-ray reflectivity, in order to characterize side chains at film surface for vertical alignment of liquid crystals. Existence thin and low density top layer at surface of polyimide film, which was considered to be side chains, was clearly detected. Furthermore, existence of high density layer just below side chain layer was also found, and it is suggested that backbone chain ordering at film surface. Effect of rubbing on VA film was not detected. However, density growth by annealing just below side chain layer of rubbed VA film suggests more ordered backbone chain alignment induced by rubbing.

[1]  Takahiro Sakai,et al.  Effects of Annealing on Rubbed Polyimide Surface Studiedby Grazing-Incidence X-Ray Diffraction , 2009, IEICE Trans. Electron..

[2]  J. A. Logan,et al.  Near-surface alignment of polymers in rubbed films , 1995, Nature.

[3]  Y. Shen,et al.  SUM-FREQUENCY VIBRATIONAL SPECTROSCOPIC STUDY OF A RUBBED POLYMER SURFACE , 1999 .

[4]  Yinghan Wang,et al.  A study of the transition of liquid-crystal alignment from homeotropic to planar on a polyimide layer , 2010 .

[5]  I. Hirosawa,et al.  Influence of Annealing on Molecular Orientation of Rubbed Polyimide Film Observed by Reflection Ellipsometry , 1997 .

[6]  Ming Li,et al.  Effect of a biphenyl side chain of polyimide on the pretilt angle of liquid crystal molecules: molecular simulation and experimental studies , 2010 .

[7]  M. Toney,et al.  Grazing incidence x-ray scattering studies of thin films of an aromatic polyimide , 1993 .

[8]  Takahiro Sakai,et al.  Effects of Rubbing Condition and Soaking Time on Surface Crystallization of Rubbed Polyimide Film by Soaking into Acetone , 2008, IEICE Trans. Electron..

[9]  H. Kimura,et al.  Characterization of Molecular Orientation of Rubbed Polyimide Film by Grazing Incidence X-ray Scattering , 1999 .

[10]  I. Hirosawa,et al.  Effect of Soaking in Solvents on Molecular Orientation of Rubbed Polyimide Film , 1999 .

[11]  Takahiro Sakai,et al.  Effect of Rubbing on Polymers for Liquid Crystal Alignment Film Studied by Grazing-Incidence X-ray Diffraction and Reflection Ellipsometry , 2007, IEICE Trans. Electron..

[12]  R. Superfine,et al.  Probing the Mechanisms for Surface-Induced Alignment of Liquid Crystals , 1991 .

[13]  Soo‐Youle Cha,et al.  Studies of Frictional Properties on TN mode Alignment Film Surfaces with AFM/FFM , 2009 .

[14]  I. Hirosawa.  Method of Characterizing Rubbed Polyimide Film for Liquid Crystal Display Devices Using Reflection Ellipsometry , 1996 .

[15]  I. Hirosawa.  Relation between Molecular Orientation and Rubbing Strength Observed by Reflection Ellipsometry , 1997 .

[16]  Y. Hirai,et al.  Molecular Orientation of Polyimide Films for Liquid Crystal Alignment Studied by Infrared Dichroism , 1994 .