Exploiting Light Interferences to Generate Micrometer-High Superstructures from Monomeric Azo Materials with Extensive Orientational Mobility

Authors

Florent Rodriguez, Nantes UniversitéFollow
Joachim Jelken, University of Western OntarioFollow
Nicolas Delpouve, Normandie UniversitéFollow
Adèle Laurent, Nantes UniversitéFollow
Bertrand Garnier, Nantes UniversitéFollow
Jean-Luc Duvail, Nantes UniversitéFollow
Francois Lagugne-Labarthet, University of Western OntarioFollow
Eléna Ishow, Nantes UniversitéFollow

Document Type

Article

Publication Date

6-14-2021

Journal

Advanced Optical Materials

Volume

9

Issue

19

Last Page

2100525

URL with Digital Object Identifier

https://doi.org/10.1002/adom.202100525

Abstract

Photochromic azo materials have stirred considerable interest for their ability to mechanically respond to polarized light through large photo-induced migration and orientation processes. In order to apprehend the microscopic dynamics behind the extensive mass transport occurring under interferential illumination, two azo compounds differing by their propen-sity to form hydrogen bonds are synthesized and processed as nondoped glassy thin films. Interferential irradiation using polarization and intensity patterns reveals fully distinct responses. Regular nanometer-high surface relief gratings transform into micrometer superstructures with an ampli-tude ten times higher than the initial film thickness when using the latter polarization. Systematic comparisons between the azo materials in terms of thermal properties, photochromism in solution and in the solid state, and photomigration are carried out. The progressive formation of super-structures is ascribed to two successive processes. The first one relates to fast photoinduced migration due to the impinging structured light, and the second one is promoted by slower thermally activated “zig-zag”-like diffu-sion and Z-E thermal relaxation, which in turn requests high orientational mobility of the azo compounds and causes large nanomechanical changes. Such studies should provide novel structural guidelines in terms of material fluidity to rapidly achieve highly structured and rewritable materials at lilogwht irradiance.

Citation of this paper:

Rodriguez, F., Jelken, J., Delpouve, N., Laurent, A., Garnier, B., Duvail, J.-L., Lagugné-Labarthet, F., Ishow, E., Exploiting Light Interferences to Generate Micrometer-High Superstructures from Monomeric Azo Materials with Extensive Orientational Mobility. Adv. Optical Mater. 2021, 9, 2100525. https://doi.org/10.1002/adom.202100525