Optical storage in azobenzene-containing epoxy polymers processed as Langmuir Blodgett films

• Published in: Materials Science & Engineering C 2013-04, Vol.33 (3), p.1403-1408
• Main Authors: Fernández, Raquel, Mondragon, Iñaki, Sanfelice, Rafaela C., Pavinatto, Felippe J., Oliveira, Osvaldo N., Oyanguren, Patricia, Galante, María J.
• Format: Article
• Language: English
• Subjects: Anisotropy; Azo Compounds - chemistry; Azocopolymers; Benzhydryl Compounds - chemistry; Benzylamines - chemistry; Epoxy; Epoxy Compounds - chemistry; Lasers; LB films; Membranes, Artificial; Optical Phenomena; Optical storage; Polymers - chemistry; Pressure; Spectrophotometry, Ultraviolet; Spin coating; Spin Labels; Surface Properties; Toluidines - chemistry
• ISSN: 0928-4931; 1873-0191
• DOI: 10.1016/j.msec.2012.12.043

In this study, azocopolymers containing different main-chain segments have been synthesized with diglycidyl ether of bisphenol A (DGEBA, DER 332, n=0.03) and the azochromophore Disperse Orange 3 (DO3) cured with two monoamines, viz. benzylamine (BA) and m-toluidine (MT). The photoinduced birefringence was investigated in films produced with these azopolymers using the spin coating (SC) and Langmuir Blodgett (LB) techniques. In the LB films, birefringence increased with the content of azochromophore and the film thickness, as expected. The nanostructured nature of the LB films led to an enhanced birefringence and faster dynamics in the writing process, compared to the SC films. In summary, the combination of azocopolymers and the LB method may allow materials with tuned properties for various optical applications, including in biological systems were photoisomerization may be used to trigger actions such as drug delivery. [Display omitted] ► Langmuir Blodgett (LB) films of epoxy-based azopolymers were obtained and analyzed. ► Optical properties of LB and spin coated (SC) films were compared. ► Azo content, structure, laser power and number of layers were main factors studied. ► LB films had larger free volume for the azobenzenes isomerization than SC. ► LB films led to higher birefringence and faster dynamics compared to SC.