Flexographic Printed Flexible Thermochromic Stickers for Smart Sensing Applications

Abstract The growing demand for thermochromic materials in areas such as food packaging requires the development of fast‐response and extended‐life materials. The use of metal cation‐ionic liquid complexes is increasing due to the easiness to tailor their properties, leading to changes in thermochro...

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Main Authors: M. Morais, J. Figueira, M. C. Corvo, M. Peixoto, D. Oliveira, A. Gonçalves, E. Fortunato, R. Martins, E. Carlos, J. V. Pinto
Format: Article
Language:English
Published: Wiley-VCH 2025-06-01
Series:Advanced Materials Interfaces
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Online Access:https://doi.org/10.1002/admi.202400972
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author M. Morais
J. Figueira
M. C. Corvo
M. Peixoto
D. Oliveira
A. Gonçalves
E. Fortunato
R. Martins
E. Carlos
J. V. Pinto
author_facet M. Morais
J. Figueira
M. C. Corvo
M. Peixoto
D. Oliveira
A. Gonçalves
E. Fortunato
R. Martins
E. Carlos
J. V. Pinto
author_sort M. Morais
collection DOAJ
description Abstract The growing demand for thermochromic materials in areas such as food packaging requires the development of fast‐response and extended‐life materials. The use of metal cation‐ionic liquid complexes is increasing due to the easiness to tailor their properties, leading to changes in thermochromic response. This work presents the synthesis and introduction of thermochromic 1‐butyl‐3‐methylimidazolium chloride and 4‐chloronickelate ([BMIm]2[NiCl4]) complexes into water‐based inks. Formulations with varying concentrations of complexes (10–40 wt.%) are printed on tags thorugh a roll‐to‐roll process and tested between 30–45 °C. Also, films with one to five layers are analyzed for color contrast and different encapsulating materials are studied to improve the thermochromic films' robustness. The optimal films, with three layers of ink with 40 wt.% complexes encapsulated with Fixomull Transparent present enhanced color contrast and fast response time. Red‐green‐blue analysis is performed on these films, revealing a blue/red ratio of 1.7 after heating at 40 °C for 30 min. This work paves the way for developing flexible stickers with fast response and high contrast. The innovative and straightforward thermochromic inks' production process and compatibility with large‐scale manufacturing show their promising future as cost‐effective stickers for smart packaging applications, such as visual indicators of ideal food consumption temperatures.
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institution Kabale University
issn 2196-7350
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publishDate 2025-06-01
publisher Wiley-VCH
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series Advanced Materials Interfaces
spelling doaj-art-e16d5492268641158f45b64216612dae2025-08-20T03:45:49ZengWiley-VCHAdvanced Materials Interfaces2196-73502025-06-011211n/an/a10.1002/admi.202400972Flexographic Printed Flexible Thermochromic Stickers for Smart Sensing ApplicationsM. Morais0J. Figueira1M. C. Corvo2M. Peixoto3D. Oliveira4A. Gonçalves5E. Fortunato6R. Martins7E. Carlos8J. V. Pinto9CENIMAT i3N Department of Materials Science School of Science and Technology NOVA University Lisbon and CEMOP/UNINOVA Caparica 2829 ‐ 516 PortugalCENIMAT i3N Department of Materials Science School of Science and Technology NOVA University Lisbon and CEMOP/UNINOVA Caparica 2829 ‐ 516 PortugalCENIMAT i3N Department of Materials Science School of Science and Technology NOVA University Lisbon and CEMOP/UNINOVA Caparica 2829 ‐ 516 PortugalCENIMAT i3N Department of Materials Science School of Science and Technology NOVA University Lisbon and CEMOP/UNINOVA Caparica 2829 ‐ 516 PortugalCENIMAT i3N Department of Materials Science School of Science and Technology NOVA University Lisbon and CEMOP/UNINOVA Caparica 2829 ‐ 516 PortugalCENIMAT i3N Department of Materials Science School of Science and Technology NOVA University Lisbon and CEMOP/UNINOVA Caparica 2829 ‐ 516 PortugalCENIMAT i3N Department of Materials Science School of Science and Technology NOVA University Lisbon and CEMOP/UNINOVA Caparica 2829 ‐ 516 PortugalCENIMAT i3N Department of Materials Science School of Science and Technology NOVA University Lisbon and CEMOP/UNINOVA Caparica 2829 ‐ 516 PortugalCENIMAT i3N Department of Materials Science School of Science and Technology NOVA University Lisbon and CEMOP/UNINOVA Caparica 2829 ‐ 516 PortugalCENIMAT i3N Department of Materials Science School of Science and Technology NOVA University Lisbon and CEMOP/UNINOVA Caparica 2829 ‐ 516 PortugalAbstract The growing demand for thermochromic materials in areas such as food packaging requires the development of fast‐response and extended‐life materials. The use of metal cation‐ionic liquid complexes is increasing due to the easiness to tailor their properties, leading to changes in thermochromic response. This work presents the synthesis and introduction of thermochromic 1‐butyl‐3‐methylimidazolium chloride and 4‐chloronickelate ([BMIm]2[NiCl4]) complexes into water‐based inks. Formulations with varying concentrations of complexes (10–40 wt.%) are printed on tags thorugh a roll‐to‐roll process and tested between 30–45 °C. Also, films with one to five layers are analyzed for color contrast and different encapsulating materials are studied to improve the thermochromic films' robustness. The optimal films, with three layers of ink with 40 wt.% complexes encapsulated with Fixomull Transparent present enhanced color contrast and fast response time. Red‐green‐blue analysis is performed on these films, revealing a blue/red ratio of 1.7 after heating at 40 °C for 30 min. This work paves the way for developing flexible stickers with fast response and high contrast. The innovative and straightforward thermochromic inks' production process and compatibility with large‐scale manufacturing show their promising future as cost‐effective stickers for smart packaging applications, such as visual indicators of ideal food consumption temperatures.https://doi.org/10.1002/admi.202400972flexographic printingionic liquidslow‐temperature transitionpermeable encapsulantsthermochromic stickers
spellingShingle M. Morais
J. Figueira
M. C. Corvo
M. Peixoto
D. Oliveira
A. Gonçalves
E. Fortunato
R. Martins
E. Carlos
J. V. Pinto
Flexographic Printed Flexible Thermochromic Stickers for Smart Sensing Applications
Advanced Materials Interfaces
flexographic printing
ionic liquids
low‐temperature transition
permeable encapsulants
thermochromic stickers
title Flexographic Printed Flexible Thermochromic Stickers for Smart Sensing Applications
title_full Flexographic Printed Flexible Thermochromic Stickers for Smart Sensing Applications
title_fullStr Flexographic Printed Flexible Thermochromic Stickers for Smart Sensing Applications
title_full_unstemmed Flexographic Printed Flexible Thermochromic Stickers for Smart Sensing Applications
title_short Flexographic Printed Flexible Thermochromic Stickers for Smart Sensing Applications
title_sort flexographic printed flexible thermochromic stickers for smart sensing applications
topic flexographic printing
ionic liquids
low‐temperature transition
permeable encapsulants
thermochromic stickers
url https://doi.org/10.1002/admi.202400972
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