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UNIVERSITY OF BUCHAREST
FACULTY OF PHYSICS Guest
2024-11-22 2:09 |
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Conference: Bucharest University Faculty of Physics 2012 Meeting
Section: Polymer Physics
Title:
Thin Film Polyimide Deposition for Liquid Crystals Cells
Authors:
D. STAICU (1), Ionelia STAICU (2)
Affiliation:
(1) University of Bucharest, Faculty of Physics, P. O. Box MG-11, Bucharest 077125
(2) Scoala cu clasele I-VIII, nr.143, Sector 5, Bucuresti
E-mail
staicu.dumitru@gmail.com
Keywords:
thin polymeric films, Polyimide, AFM, liquid crystals cell
Abstract:
We analyzed deposition of thin polymeric films using spin coating method and nanolithography with a Veeco AFM used in contact mode. Various writing patterns have been used with distances of 100-500 nm between two adjacent lines and a contact force of 0.3-5 µN.Polyimide thin films have been deposed by Spin Coating Method at 2000 rpm during20 seconds and then heat-treated at 80°C for 5 minutes and then at 200°C for 40 minutes. After AFM analysis, we noted that the obtained films are uniform and homogeneous, without variation in topography. The model of AFM used has a maximum read/scan surface of 100 x 100 µN.
After writing the patterns on the surface of the polyimide thin films, the written areas were scanned using the same AFM, in order to examine the depth of the grooves created as a function of the applied writing force. Using an optical microscope to analyze the image of patterns, we found a better contrast for a writing with a relative bigger force of about 4 µN, and a difference in the contrast between the areas written at different angles.
The experimental results indicate that the increase of the density of the writing lines and of the writing force induce a better alignment of the nematic liquid crystal molecules.
Note: D. STAICU was supported by the doctoral grant of the Ministry of Education, Research, Youth and Sport 2011.
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