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

Abstract

a b s t r a c tThis study focuses on the characterization of sulphonated calix[4]arene derivative films coated on a quartz substrate with a thickness of 40 nm by spin coating method for humidity detection. The humidity adsorption kinetics of the sulphonated calix[4]arene films was investigated by quartz crystal microbalance (QCM) technique. The Langmuir model was used to determine the adsorption rates and Gibbs free energy for various relative humidities between 11% and 97%. Our reproducible experimental results show that suphonated calix[4]arene films have a great potential for humidity sensing applications at room temperature operations.

Humidity adsorption kinetics of a trypsin gel film

“…The Langmuir adsorption isotherm model was used to analyze our adsorption data to explain the adsorption-desorption behavior of gas molecules as given in Okur et al [24]. Basically, the relationship between the surface adsorption rate and frequency shift (Df) QCM can be expressed as…”

“…Humidity standards were provided in a closed box system partially filled with saturated salts with various relative levels between 11% and 97% RH. The set up used to observe the hydration-dehydration kinetics of the gel layer using the standard salt solutions was described in details in our previous work [24].…”

Humidity sensing properties of novel ruthenium polypyridyl complex

“…At any temperature, the concentration of a saturated solution is fixed. With the excess solute, the solution remains saturated in a sealed metal or a glass chamber [21]. The temperature was kept constant during measurements around 23 • C. The vapour molar concentration C was calculated from the ideal gas equation (PV = nRT).…”

“…At the corresponding partial pressure for the relative humidity measured at the equilibrium point as given in Table 1 shown in Refs. [21,30]. The time variation of the change in the frequency due to adsorption can be obtained by…”

“…[21]. The same experimental setup given in our previous work [21] was used to measure the adsorption kinetics of Ru-PC films above saturated LiCl (11% RH) and K 2 SO 4 (97% RH) aquatic solution level inside a half filled closed container.…”