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Photopatternable Epoxy-Based Thermosets

The present work provides a comparative study on the photopatterning of epoxy-based thermosets as a function of network structure and network mobility. Local switching of solubility properties by light of a defined wavelength is achieved by exploiting versatile o-nitrobenzyl ester (o-NBE) chemistry....

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Detalles Bibliográficos
Autores principales: Giebler, Michael, Radl, Simone, Ules, Thomas, Griesser, Thomas, Schlögl, Sandra
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2019
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6695657/
https://www.ncbi.nlm.nih.gov/pubmed/31344852
http://dx.doi.org/10.3390/ma12152350
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author Giebler, Michael
Radl, Simone
Ules, Thomas
Griesser, Thomas
Schlögl, Sandra
author_facet Giebler, Michael
Radl, Simone
Ules, Thomas
Griesser, Thomas
Schlögl, Sandra
author_sort Giebler, Michael
collection PubMed
description The present work provides a comparative study on the photopatterning of epoxy-based thermosets as a function of network structure and network mobility. Local switching of solubility properties by light of a defined wavelength is achieved by exploiting versatile o-nitrobenzyl ester (o-NBE) chemistry. o-NBE derivatives with terminal epoxy groups are synthetized and thermally cured with different types of cycloaliphatic anhydrides via nucleophilic ring opening reaction. By varying the structure of the anhydride, glass transition temperature (T(g)) and surface hardness are adjusted over a broad range. Once the network has been formed, the photolysis of the o-NBE groups enables a well-defined degradation of the 3D network. Fourier transform infrared (FT-IR) spectroscopy studies demonstrate that cleavage rate and cleavage yield increase with rising mobility of the network, which is either facilitated by inherent network properties (T(g) below room temperature) or a simultaneous heating of the thermosets above their T(g). The formation of soluble species is evidenced by sol-gel analysis, revealing that low-T(g) networks are prone to secondary photoreactions at higher exposure doses, which lead to a re-crosslinking of the cleaved polymer chains. The change in solubility properties is exploited to inscribe positive tone micropatterns within the thermosets by photolithographic techniques. Contrast curves show that the resist performance of rigid networks is superior to flexible ones, with a contrast of 1.17 and a resolution of 8 µm.
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spelling pubmed-66956572019-09-05 Photopatternable Epoxy-Based Thermosets Giebler, Michael Radl, Simone Ules, Thomas Griesser, Thomas Schlögl, Sandra Materials (Basel) Article The present work provides a comparative study on the photopatterning of epoxy-based thermosets as a function of network structure and network mobility. Local switching of solubility properties by light of a defined wavelength is achieved by exploiting versatile o-nitrobenzyl ester (o-NBE) chemistry. o-NBE derivatives with terminal epoxy groups are synthetized and thermally cured with different types of cycloaliphatic anhydrides via nucleophilic ring opening reaction. By varying the structure of the anhydride, glass transition temperature (T(g)) and surface hardness are adjusted over a broad range. Once the network has been formed, the photolysis of the o-NBE groups enables a well-defined degradation of the 3D network. Fourier transform infrared (FT-IR) spectroscopy studies demonstrate that cleavage rate and cleavage yield increase with rising mobility of the network, which is either facilitated by inherent network properties (T(g) below room temperature) or a simultaneous heating of the thermosets above their T(g). The formation of soluble species is evidenced by sol-gel analysis, revealing that low-T(g) networks are prone to secondary photoreactions at higher exposure doses, which lead to a re-crosslinking of the cleaved polymer chains. The change in solubility properties is exploited to inscribe positive tone micropatterns within the thermosets by photolithographic techniques. Contrast curves show that the resist performance of rigid networks is superior to flexible ones, with a contrast of 1.17 and a resolution of 8 µm. MDPI 2019-07-24 /pmc/articles/PMC6695657/ /pubmed/31344852 http://dx.doi.org/10.3390/ma12152350 Text en © 2019 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
Giebler, Michael
Radl, Simone
Ules, Thomas
Griesser, Thomas
Schlögl, Sandra
Photopatternable Epoxy-Based Thermosets
title Photopatternable Epoxy-Based Thermosets
title_full Photopatternable Epoxy-Based Thermosets
title_fullStr Photopatternable Epoxy-Based Thermosets
title_full_unstemmed Photopatternable Epoxy-Based Thermosets
title_short Photopatternable Epoxy-Based Thermosets
title_sort photopatternable epoxy-based thermosets
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6695657/
https://www.ncbi.nlm.nih.gov/pubmed/31344852
http://dx.doi.org/10.3390/ma12152350
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AT schloglsandra photopatternableepoxybasedthermosets