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Seeing the Unseen: The Role of Liquid Crystals in Gas-Sensing Technologies

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Detalhes bibliográficos
Resumo:Fast, real-time detection of gases and volatile organic compounds (VOCs) is an emerging research field relevant to most aspects of modern society, from households to health facilities, industrial units, and military environments. Sensor features such as high sensitivity, selectivity, fast response, and low energy consumption are essential. Liquid crystal (LC)-based sensors fulfill these requirements due to their chemical diversity, inherent self-assembly potential, and reversible molecular order, resulting in tunable stimuli-responsive soft materials. Sensing platforms utilizing thermotropic uniaxial systems—nematic and smectic—that exploit not only interfacial phenomena, but also changes in the LC bulk, are demonstrated. Special focus is given to the different interaction mechanisms and tuned selectivity toward gas and VOC analytes. Furthermore, the different experimental methods used to transduce the presence of chemical analytes into macroscopic signals are discussed and detailed examples are provided. Future perspectives and trends in the field, in particular the opportunities for LC-based advanced materials in artificial olfaction, are also discussed.
Autores principais:Esteves, Carina
Outros Autores:Ramou, Efthymia; Porteira, Ana Raquel Pina; Moura Barbosa, Arménio Jorge; Roque, Ana Cecília Afonso
Assunto:gas sensing liquid crystals self-assembly soft functional materials volatile organic compounds Electronic, Optical and Magnetic Materials Atomic and Molecular Physics, and Optics SDG 7 - Affordable and Clean Energy
Ano:2020
País:Portugal
Tipo de documento:recensão
Tipo de acesso:acesso aberto
Instituição associada:Universidade Nova de Lisboa
Idioma:inglês
Origem:Repositório Institucional da UNL
Descrição
Resumo:Fast, real-time detection of gases and volatile organic compounds (VOCs) is an emerging research field relevant to most aspects of modern society, from households to health facilities, industrial units, and military environments. Sensor features such as high sensitivity, selectivity, fast response, and low energy consumption are essential. Liquid crystal (LC)-based sensors fulfill these requirements due to their chemical diversity, inherent self-assembly potential, and reversible molecular order, resulting in tunable stimuli-responsive soft materials. Sensing platforms utilizing thermotropic uniaxial systems—nematic and smectic—that exploit not only interfacial phenomena, but also changes in the LC bulk, are demonstrated. Special focus is given to the different interaction mechanisms and tuned selectivity toward gas and VOC analytes. Furthermore, the different experimental methods used to transduce the presence of chemical analytes into macroscopic signals are discussed and detailed examples are provided. Future perspectives and trends in the field, in particular the opportunities for LC-based advanced materials in artificial olfaction, are also discussed.