Optical humidity sensor using methylene blue immobilized on a hydrophilic polymer

Fernández-Ramos, M.D.; Ordóñez, Yadira F.; Capitán-Vallvey, L.F.; Vargas-Sansalvador, Isabel M. Pérez de; Ballesta-Claver, J.

doi:10.1016/j.snb.2015.06.006

Cited by 24 publications

(8 citation statements)

References 38 publications

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“…The visible spectra of methylene blue adsorbed in mesoporous silica show two characteristic absorption peaks of MB at 620 and 665 nm (Figure 3A), similar to the literature [38]. Preliminary tests were performed to evaluate the sensor response as a function of humidity.…”

Section: Resultssupporting

confidence: 66%

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Real-Time Ozone Sensor Based on Selective Oxidation of Methylene Blue in Mesoporous Silica Films

Ghazaly

Hébrant

Langlois

et al. 2019

Sensors

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Sensitive and selective personal exposure monitors are needed to assess ozone (O3) concentrations in the workplace atmosphere in real time for the analysis and prevention of health risks. Here, a cumulative gas sensor using visible spectroscopy for real-time O3 determination is described. The sensing chip is a mesoporous silica thin film deposited on transparent glass and impregnated with methylene blue (MB). The sensor is reproducible, stable for at least 50 days, sensitive to 10 ppb O3 (one-tenth of the occupational exposure limit value in France, Swiss, Canada, U.K., Japan, and the USA) with a measurement range tested up to 500 ppb, and insensitive to NO2 and to large variation in relative humidity. A model and its derivative as a function of time are proposed to convert in real time the sensor response to concentrations, and an excellent correlation was obtained between those data and reference O3 concentrations. This sensor is based on a relatively cheap sensing material and a robust detection system, and its analytical performance makes it suitable for monitoring real-time O3 concentrations in workplaces to promote a safer environment for workers.

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Section: Resultssupporting

confidence: 66%

“…For that purpose, we chose methylene blue (MB), a blue cationic dye that belongs to the phenothiazine family. In previous studies, MB was used to monitor humidity [37,38,39]. The degradation of MB in aqueous solution by O 3 was studied by Zhang et al [40] and by Al Jibouri et al [41].…”

Section: Introductionmentioning

confidence: 99%

Real-Time Ozone Sensor Based on Selective Oxidation of Methylene Blue in Mesoporous Silica Films

Ghazaly

Hébrant

Langlois

et al. 2019

Sensors

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“…To further demonstrate the advantages of our designed sensor, we compare the humidity sensing performances of Cu perovskite NP lms with those of other optical humidity sensors (Table 1). 6,[36][37][38][39] Our humidity sensor with the MA 2 CuBr 4 lm exhibits a wide RH sensing range and comparable response time.…”

Section: Resultsmentioning

confidence: 99%

Optical humidity sensors based on lead-free Cu-based perovskite nanomaterials

Lee

Jin

et al. 2022

Nanoscale Adv.

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“…Usually, humidity sensors are based on metal oxide semiconductors, conducting polymers, carbon nanotubes, and/or graphene oxides. At room temperature, the adsorption of water vapor/molecules changes the resistance or the capacitance of the sensing film [4][5][6][7][8][9][10][11][12][13][14][15].…”

Section: Introductionmentioning

confidence: 99%

Biochars as Innovative Humidity Sensing Materials

et al. 2017

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In this work, biochar-based humidity sensors were prepared by drop-coating technique. Polyvinylpyrrolidone (PVP) was added as an organic binder to improve the adhesion of the sensing material onto ceramic substrates having platinum electrodes. Two biochars obtained from different precursors were used. The sensors were tested toward relative humidity (RH) at room temperature and showed a response starting around 5 RH%, varying the impedance of 2 orders of magnitude after exposure to almost 100% relative humidity. In both cases, biochar materials are behaving as p-type semiconductors under low amounts of humidity. On the contrary, for higher RH values, the impedance decreased due to water molecules adsorption. When PVP is added to SWP700 biochar, n-p heterojunctions are formed between the two semiconductors, leading to a higher sensitivity at low RH values for the sensors SWP700-10% PVP and SWP700-20% PVP with respect to pure SWP700 sensor. Finally, response and recovery times were both reasonably fast (in the order of 1 min).

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Optical humidity sensor using methylene blue immobilized on a hydrophilic polymer

Cited by 24 publications

References 38 publications

Real-Time Ozone Sensor Based on Selective Oxidation of Methylene Blue in Mesoporous Silica Films

Real-Time Ozone Sensor Based on Selective Oxidation of Methylene Blue in Mesoporous Silica Films

Optical humidity sensors based on lead-free Cu-based perovskite nanomaterials

Biochars as Innovative Humidity Sensing Materials

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