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Modeling of Stripe Patterns in Photosensitive Azopolymers
Placed at interfaces, azobenzene-containing materials show extraordinary phenomena when subjected to external light sources. Here we model the surface changes induced by one-dimensional Gaussian light fields in thin azopolymer films. Such fields can be produced in a quickly moving film irradiated wi...
Autores principales: | , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
MDPI
2020
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7240688/ https://www.ncbi.nlm.nih.gov/pubmed/32224848 http://dx.doi.org/10.3390/polym12040735 |
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author | Yadav, Bharti Domurath, Jan Saphiannikova, Marina |
author_facet | Yadav, Bharti Domurath, Jan Saphiannikova, Marina |
author_sort | Yadav, Bharti |
collection | PubMed |
description | Placed at interfaces, azobenzene-containing materials show extraordinary phenomena when subjected to external light sources. Here we model the surface changes induced by one-dimensional Gaussian light fields in thin azopolymer films. Such fields can be produced in a quickly moving film irradiated with a strongly focused laser beam or illuminating the sample through a cylindrical lens. To explain the appearance of stripe patterns, we first calculate the unbalanced mechanical stresses induced by one-dimensional Gaussian fields in the interior of the film. In accordance with our orientation approach, the light-induced stress originates from the reorientation of azobenzenes that causes orientation of rigid backbone segments along the light polarization. The resulting volume forces have different signs and amplitude for light polarization directed perpendicular and parallel to the moving direction. Accordingly, the grooves are produced by the stretching forces and elongated protrusions by the compressive forces. Implementation into a viscoplastic model in a finite element software predicts a considerably weaker effect for the light polarized along the moving direction, in accordance with the experimental observations. The maximum value in the distribution of light-induced stresses becomes in this case very close to the yield stress which results in smaller surface deformations of the glassy azopolymer. |
format | Online Article Text |
id | pubmed-7240688 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2020 |
publisher | MDPI |
record_format | MEDLINE/PubMed |
spelling | pubmed-72406882020-06-11 Modeling of Stripe Patterns in Photosensitive Azopolymers Yadav, Bharti Domurath, Jan Saphiannikova, Marina Polymers (Basel) Article Placed at interfaces, azobenzene-containing materials show extraordinary phenomena when subjected to external light sources. Here we model the surface changes induced by one-dimensional Gaussian light fields in thin azopolymer films. Such fields can be produced in a quickly moving film irradiated with a strongly focused laser beam or illuminating the sample through a cylindrical lens. To explain the appearance of stripe patterns, we first calculate the unbalanced mechanical stresses induced by one-dimensional Gaussian fields in the interior of the film. In accordance with our orientation approach, the light-induced stress originates from the reorientation of azobenzenes that causes orientation of rigid backbone segments along the light polarization. The resulting volume forces have different signs and amplitude for light polarization directed perpendicular and parallel to the moving direction. Accordingly, the grooves are produced by the stretching forces and elongated protrusions by the compressive forces. Implementation into a viscoplastic model in a finite element software predicts a considerably weaker effect for the light polarized along the moving direction, in accordance with the experimental observations. The maximum value in the distribution of light-induced stresses becomes in this case very close to the yield stress which results in smaller surface deformations of the glassy azopolymer. MDPI 2020-03-26 /pmc/articles/PMC7240688/ /pubmed/32224848 http://dx.doi.org/10.3390/polym12040735 Text en © 2020 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/). |
spellingShingle | Article Yadav, Bharti Domurath, Jan Saphiannikova, Marina Modeling of Stripe Patterns in Photosensitive Azopolymers |
title | Modeling of Stripe Patterns in Photosensitive Azopolymers |
title_full | Modeling of Stripe Patterns in Photosensitive Azopolymers |
title_fullStr | Modeling of Stripe Patterns in Photosensitive Azopolymers |
title_full_unstemmed | Modeling of Stripe Patterns in Photosensitive Azopolymers |
title_short | Modeling of Stripe Patterns in Photosensitive Azopolymers |
title_sort | modeling of stripe patterns in photosensitive azopolymers |
topic | Article |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7240688/ https://www.ncbi.nlm.nih.gov/pubmed/32224848 http://dx.doi.org/10.3390/polym12040735 |
work_keys_str_mv | AT yadavbharti modelingofstripepatternsinphotosensitiveazopolymers AT domurathjan modelingofstripepatternsinphotosensitiveazopolymers AT saphiannikovamarina modelingofstripepatternsinphotosensitiveazopolymers |