Humidity Sensors Using Chemically Modified Polymer Thin Films

Sakai, Yoshiro; Matsuguchi, Masanobu

doi:10.5796/electrochemistry.67.950

Cited by 15 publications

(5 citation statements)

References 31 publications

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“…Non-ionic but very polar polyimides and esters are suitable candidates for microwave humidity sensors whose sensing mechanism is based on the variation of dielectric properties as a function of humidity [4]. The effects of moisture on the dielectric constant of some organic polymers films such as Poly(vinyl cinnamate) (PVCi) or Poly(methyl methacrylate) (PMMA) have been investigated through resistive-type or impedance-type sensors in low frequencies [5,6].…”

Section: Introductionmentioning

confidence: 99%

Environmentally-friendly cellulose nanofibre sheets for humidity sensing in microwave frequencies

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Boubekeur

et al. 2017

Sensors and Actuators B: Chemical

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Section: Introductionmentioning

confidence: 99%

Environmentally-friendly cellulose nanofibre sheets for humidity sensing in microwave frequencies

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Bideau

Boubekeur

et al. 2017

Sensors and Actuators B: Chemical

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“…Fabrication of composite materials including polymers into nanoscale structures is attractive to meet increasing demands in the miniaturization of devices. One of the promising approaches in this line is devices based on polymer thin films that considerably affected the miniaturization and durability of transistors, , sensors, , photodetectors, LEDs, and nonvolatile memory devices . However, unusual rupturing of nanoscale (≤100 nm) polymer films by dewetting – inorganic and organic substrates due to long-range van der Waals forces is a limitation for advanced applications of polymer thin films.…”

Section: Introductionmentioning

confidence: 99%

Relations between Dewetting of Polymer Thin Films and Phase-Separation of Encompassed Quantum Dots

et al. 2008

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Incorporation of semiconductor quantum dots (QDs) at high densities in polymer thin films is promising for the development of nanoscale sensors, light-emitting diodes, and photovoltaic devices. However, inhomogeneous distribution and aggregation of QDs in polymers limit the applications of QD-polymer composites. We investigated the origin of the aggregation of CdSe-ZnS QDs in polybutadiene (PB) thin films and its relations with the dewetting of polymer thin films on inorganic surfaces. Microscale dewetting of PB thin films on glass surfaces resulted in the formation of honeycomb structures of PB, and nanoscale dewetting on the QD surface resulted in phase-separation and aggregation of QDs. The formation of the honeycomb structures of PB is attributed to phase-separation between PB and glass during the dewetting on the glass surface, and the aggregation of QDs is attributed to the phase-separation between PB and QDs during the dewetting on the QD surface. The honeycomb structures of PB are characterized using optical microscopy and atomic force microscopy (AFM) imaging, and the phase-separation and aggregation of QDs are characterized using transmission electron microscopy (TEM) imaging and inter-QD Förster resonance energy-transfer (FRET). FRET is confirmed from photoluminescence (PL) spectral shifts and decreases of PL intensity and lifetime of QDs. Without the phase-separation and aggregation of QDs, inter-QD FRET is unexpected under the selected densities of QDs; the calculated inter-QD distance (>60 nm) for a homogeneous distribution of QDs is beyond the Förster distance (<10 nm). The phase-separation and aggregation of QDs in PB thin films are further characterized based on a decrease of FRET from QD to rhodamine 590 (R590) with an increase in the density of QDs. The aggregation of QDs occurs because of the rejection of QDs by PB molecules during the release of recoiling energy, which is distributed among entangled polymer chains and between polymer chains and QDs in the thin films. In the current work, we characterized the nanoscale dewetting of PB on the surface of QDs, the phase-separation and aggregation of QDs in PB thin films, and the limit of close-packing of QDs in polymer thin films without aggregation that are valuable during the construction of QD and polymer-based thin-film devices.

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“…Two types of materials are thus involved in water adsorption mechanisms: carboxyl groups provided by TEMPO oxidation, hydroxyl groups provided by PVOH chains and the cellulose fibers. PVOH shown low hysteresis characteristics and demonstrated wide frequency range (0.2 -20 GHz) in sensing humidity [32,37]. The sensitivity of the sensor originates from the superposition of TOCN and PVOH sensing mechanisms.…”

Section: Pvoh Contributionmentioning

confidence: 99%

TEMPO-oxidized cellulose nanofibre (TOCN) films and composites with PVOH as sensitive dielectrics for microwave humidity sensing

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Bideau

Loranger

et al. 2019

Sensors and Actuators B: Chemical

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Humidity Sensors Using Chemically Modified Polymer Thin Films

Cited by 15 publications

References 31 publications

Environmentally-friendly cellulose nanofibre sheets for humidity sensing in microwave frequencies

Environmentally-friendly cellulose nanofibre sheets for humidity sensing in microwave frequencies

Relations between Dewetting of Polymer Thin Films and Phase-Separation of Encompassed Quantum Dots

TEMPO-oxidized cellulose nanofibre (TOCN) films and composites with PVOH as sensitive dielectrics for microwave humidity sensing

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