Liquid Crystals with Interfacial Ordering that Enhances Responsiveness to Chemical Targets

Nayani, Karthik; Rai, Prabin; Bao, Nanqi; Yu, Hua-yin; Mavrikakis, Manos; Twieg, Robert J.; Abbott, Nicholas L.

doi:10.1002/adma.201706707

Cited by 50 publications

(50 citation statements)

References 35 publications

(10 reference statements)

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“…Finally, we should mention the work conducted by Nayani et al [ 133 ] In this work, it was demonstrated that the response and sensitivity to gas analytes can be improved substantially by customizing the properties of the employed LC system. The authors synthesized a nitrile‐based LC mixture that assumes a planar configuration at the LC/air interface, contrary to the propensity for a homeotropical arrangement exhibited by cyanobiphenyl LCs, yet it maintains its chemoresponsiveness upon deposition on a metal‐cation functionalized surface (in this study, La 3+ perchlorate).…”

Section: Functional Liquid Crystal Materialsmentioning

confidence: 95%

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

Esteves

Ramou

Porteira

et al. 2020

Advanced Optical Materials

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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.

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Section: Functional Liquid Crystal Materialsmentioning

confidence: 95%

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

Esteves

Ramou

Porteira

et al. 2020

Advanced Optical Materials

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“…In contrast, films of nematic 5CB supported on surfaces decorated with Ni(ClO 4 ) 2 and subsequently exposed to humid Cl 2 , exhibited no measurable orientational response (Figure , black curve; Supporting Information, Figure S6). Additional discussion of the origin of the sigmoidal shape of the response curve evident in Figure a is given in the Supporting Information …”

Section: Methodsmentioning

confidence: 99%

Redox‐Triggered Orientational Responses of Liquid Crystals to Chlorine Gas

et al. 2018

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Surface‐supported liquid crystals (LCs) that exhibit orientational and thus optical responses upon exposure to ppb concentrations of Cl2 gas are reported. Computations identified Mn cations as candidate surface binding sites that undergo redox‐triggered changes in the strength of binding to nitrogen‐based LCs upon exposure to Cl2 gas. Guided by these predictions, μm‐thick films of nitrile‐ or pyridine‐containing LCs were prepared on surfaces decorated with Mn2+ binding sites as perchlorate salts. Following exposure to Cl2, formation of Mn4+ (in the form of MnO2 microparticles) was confirmed and an accompanying change in the orientation and optical appearance of the supported LC films was measured. In unoptimized systems, the LC orientational transitions provided the sensitivity and response times needed for monitoring human exposure to Cl2 gas. The response was also selective to Cl2 over other oxidizing agents such as air or NO2 and other chemical targets such as organophosphonates.

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“…Small molecules are another type of flexible substance used in fabricating flexible sensors. [ 261 ] By molecular modifications, small‐molecule materials can present an acceptor–donor–acceptor characteristic, which has demonstrated promising application potentials on fabricating flexible electronic devices. Kim et al [ 262 ] reported their fabrication of flexible ambipolar FETs using different electron‐accepting functional groups (dicyanovinyl, cyanorhodanine, and cyanoindanone, INCN) to modify oligothiophene–phenylene molecules.…”

Section: Strategies Toward the Optimization Of F‐fet Sensorsmentioning

confidence: 99%

Recent Advances in Flexible Field‐Effect Transistors toward Wearable Sensors

Han

Zhou

2020

Advanced Intelligent Systems

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The introduction of the "Internet of Things" (IoTs) concept has spawned a series of research and development of wearable sensors. Flexible field-effect transistors (FETs) are considered to be potential sensing devices due to the variety of material utilization and the self-amplifying function on electrical signals. FETs have demonstrated the ability of detecting different kinds of external stimuli and continuous monitoring functionalities. Herein, the recent progress achieved by the academia in wearable sensors based on flexible FETs, including pressure, temperature, chemical, and biological analytes, which are vital for the manufacturing of smart wearable devices, is summarized. The sensing mechanism for different sensors is introduced and an in-depth discussion is presented, including material engineering, problems at the current stage, and future challenges.

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Liquid Crystals with Interfacial Ordering that Enhances Responsiveness to Chemical Targets

Cited by 50 publications

References 35 publications

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

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

Redox‐Triggered Orientational Responses of Liquid Crystals to Chlorine Gas

Recent Advances in Flexible Field‐Effect Transistors toward Wearable Sensors

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