Chemical gas sensors using chiral nematic liquid crystals and its applications

Kek, Khai Jun; Lee, Jovia Jia Zhen; Otono, Yuki; Ishihara, Seiya

doi:10.1002/jsid.560

Cited by 13 publications

(4 citation statements)

References 16 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The incorporation of chiral LC systems in gas sensing devices ( Table 5 ) typically takes advantage of the fact that the presence of solvent vapors can result in either a change of the helical twisting power of the chiral dopant due to reaction with the analyte or physical swelling of the system with a change of order in the LC phase, which ultimately changes the helical pitch due to absorption of the analyte. Both mechanisms lead to a shift of the selective reflection band which can be observed with the naked eye [ 146–152 ] ( Figure ).…”

Section: Functional Liquid Crystal Materialsmentioning

confidence: 99%

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

Esteves

Ramou

Porteira

et al. 2020

Advanced Optical Materials

View full text Add to dashboard Cite

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.

show abstract

Section: Functional Liquid Crystal Materialsmentioning

confidence: 99%

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

Esteves

Ramou

Porteira

et al. 2020

Advanced Optical Materials

View full text Add to dashboard Cite

show abstract

“…This principle was adopted in the work by Kek et al [ 95 , 96 ], using carefully-chosen cholesteric LCs to detect a wide variety of VOCs. It was found that the reduction of the elastic constant of cholesteric LCs resulted in a red shift of the λ max , whereas a blue shift of λ max was observed upon contact of VOCs with cholesteric LC mixtures that consist of Schiff-base, ester linkages, tolan or phenylcyclohexyl derivatives [ 95 ]. The authors made efforts to improve the sensitivity of the VOC detection by adding phenylpyrimidine to the cholesteric LCs.…”

Section: Increasing Detection Limits and Sensitivitymentioning

confidence: 99%

“…The authors made efforts to improve the sensitivity of the VOC detection by adding phenylpyrimidine to the cholesteric LCs. Due to the reduction of the nematic-isotropic transition temperature, distinct changes in peak wavelength were observed [ 95 ]. This provides evidence that the method described above has the potential to provide selective and sensitive means of VOC detection.…”

Section: Increasing Detection Limits and Sensitivitymentioning

confidence: 99%

Thermotropic Liquid Crystal-Assisted Chemical and Biological Sensors

et al. 2017

View full text Add to dashboard Cite

In this review article, we analyze recent progress in the application of liquid crystal-assisted advanced functional materials for sensing biological and chemical analytes. Multiple research groups demonstrate substantial interest in liquid crystal (LC) sensing platforms, generating an increasing number of scientific articles. We review trends in implementing LC sensing techniques and identify common problems related to the stability and reliability of the sensing materials as well as to experimental set-ups. Finally, we suggest possible means of bridging scientific findings to viable and attractive LC sensor platforms.

show abstract

“…NLC can be used as an ethanol gas sensing material. When NLC molecules absorb ethanol gas molecules, which can be regarded as a process in which NLC molecular cavity phagocytosis engulfs ethanol molecules with an enzyme-like mechanism [9,10].…”

Section: Introductionmentioning

confidence: 99%

High sensitivity ethanol vapor sensor based on a nematic liquid crystal film embedded optical fiber Sagnac interferometer

Chen

et al. 2023

J. Phys. D: Appl. Phys.

View full text Add to dashboard Cite

Interferometric optical fiber sensors have become the preferred choice for ethanol vapor detection because of their high sensitivity and figure of merit. However, the response time of interferometric fiber optic ethanol vapor sensors is long. To address this issue, we experimentally investigated an ethanol vapor sensor based on a nematic liquid crystal (NLC) film embedded optical fiber Sagnac interferometer. The high birefringent NLC film, which worked as the sensing media of ethanol vapor for its absorption of ethanol vapor, was penetrated into the Sagnac ring to generate the spectral interference. The results showed that the measurement sensitivity of ethanol gas concentration reached 2.22 pm/ppm. The detection range was about 1210 -10000 ppm. Most importantly, the response time of the proposed sensor is only 15 seconds. The designed sensor, which showed the advantages of fast response, high sensitivity, and stability, could be a competitive candidate for ethanol vapor sensing.

show abstract

Chemical gas sensors using chiral nematic liquid crystals and its applications

Cited by 13 publications

References 16 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

Thermotropic Liquid Crystal-Assisted Chemical and Biological Sensors

High sensitivity ethanol vapor sensor based on a nematic liquid crystal film embedded optical fiber Sagnac interferometer

Contact Info

Product

Resources

About