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Effects of solvent, film thickness, and hydrogen bonding on surface‐relief gratings
Author(s) -
Jung WooHyuk,
Lee KiTae,
Lee DongHan,
Han SangCheol,
Kim Yang,
Lee JangOo
Publication year - 2009
Publication title -
polymer engineering and science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.503
H-Index - 111
eISSN - 1548-2634
pISSN - 0032-3888
DOI - 10.1002/pen.21222
Subject(s) - materials science , diazo , aniline , photoisomerization , polyurethane , polymer , polymer chemistry , photochemistry , chemical engineering , composite material , organic chemistry , isomerization , chemistry , engineering , catalysis
This work focuses on the development of a new type of surface‐relief grating (SRG) using more effective materials than a typical epoxy‐based azopolymer for the recording layer of optical data storage. Thus, aniline‐based azopolymers were synthesized by reaction of N,N ‐diglycidylaniline with aniline (An) followed by diazocoupling with 4‐aminobenzonitrile or 4‐nitroaniline. Such azopolymers when spin‐cast from THF/dioxane showed better diffraction efficiency than those cast from THF alone due to residual dioxane creating a large free volume in the solid state. A second diazocoupling reaction of the diazopolymers initially obtained produced polymers with bis (diazobenzene) substituents which exhibited a higher saturation level of the diffraction efficiency for a thicker than for a thinner film. Azopolymers in which the diazo substituents incorporated hydroxyl groups ortho to the diazo unit were obtained via the reaction of the diglycidyl ether of bisphenol‐A with aniline or 3‐hydroxyaniline followed by coupling with diazotised hydroxynitroaminobenzene. These hydroxy groups, presumably as a result of their H‐bonding to the diazo‐N, effectively prevented the photoisomerization of the chromophores, so that the polymers showed no SRG at a normal laser intensity of 100 mW/cm 2 . Polyurethane‐based azopolymers, synthesized with toluene‐2,4‐diisocyanate and disperse orange 17 containing no hydroxyl groups in the main chains, showed better diffraction efficiency than the other azopolymers with nitro group substituents. POLYM. ENG. SCI., 2009. © 2009 Society of Plastics Engineers