Study of adsorption behaviors of meso-tetrakis (4-N-Methylpyridyl) porphine p-Toluenesulfonate at indium–tin-oxide electrode/solution interface by in-situ internal reflection spectroscopy and cyclic voltammetry

Seker

et al. 2011

Ind. Eng. Chem. Res.

Thin films of CdS nanoparticles were synthesized by the chemical bath deposition (CBD) technique to investigate humidity response characteristics. The morphology and the crystal structure of CdS thin films were investigated by scanning electron microscopy (SEM) and X-ray diffraction (XRD), respectively. The quartz crystal microbalance (QCM) technique was used to measure the water vapor adsorption and desorption rates of CdS thin films. The dynamic Langmuir model was used to analyze the kinetics of the moisture adsorption and desorption process under relative humidity (RH) between 17 and 85% RH. Our results indicate that CdS thin films have a great affinity to humidity at room temperature.

Section: Theoretical Analysis Of Qcm Results Using Modifiedmentioning

confidence: 94%

Humidity Sensing Properties of CdS Nanoparticles Synthesized by Chemical Bath Deposition Method

Demir

Seker

et al. 2011

Ind. Eng. Chem. Res.

“…The corresponding Gibbs free energy G of adsorption/desorption process at a constant temperature can be calculated with G = − RT ln K eq [36], where K eq is equilibrium constant (K eq = k a /k d ), R is the universal gas constant and T is the temperature (298 K). The calculated equilibrium constant K eq and Gibbs free energy values are 234,939 and −30.64 kJ/mol for the adsorbed water mass between 10% and 90% RH, respectively.…”

Section: Theoretical Analysis Of Qcm Results Using Modified Langmuir mentioning

confidence: 99%

Humidity sensing properties of ZnO-based fibers by electrospinning

Horzum

Taşçıoglu

et al. 2011

Talanta

a b s t r a c tZinc oxide (ZnO) based fibers with a diameter of 80-100 nm were prepared by electrospinning. Polyvinyl alcohol (PVA) and zinc acetate dihydrate were dissolved in water and the polymer/salt solution was electrospun at 2.5 kV cm −1 . The resulting electrospun fibers were subjected to calcination at 500• C for 2 h to obtain ZnO-based fibers. Humidity sensing properties of the fiber mats were investigated by quartz crystal microbalance (QCM) method and electrical measurements. The adsorption kinetics under constant relative humidity (RH) between 10% and 90% were explained using Langmuir adsorption model. Results of the measurements showed that ZnO-based fibers were found to be promising candidate for humidity sensing applications at room temperature.

“…The Gibbs free energy G of adsorption/desorption process in terms of K equ at a given temperature is defined as [25]:…”

Section: Resultsmentioning

confidence: 99%

Humidity adsorption kinetics of water soluble calix[4]arene derivatives measured using QCM technique

Sensors and Actuators B: Chemical

Kuş

Özel

2010

a b s t r a c tWe report on the optimization and characterization of water soluble calix [4]arene derivative as a humidity sensor based on quartz crystal microbalance technique. The moisture adsorption and desorption kinetics of calix[4]arene were investigated. The Langmuir model was used to determine the kinetic parameters such as adsorption, desorption rates and Gibbs free energy between relative humidity between 29% and 78%. Reproducible experimental results were obtained showing that water soluble calix[4]arene films have a great potential for humidity sensing applications at room temperature operations.