Competitive sorption of water vapor and CO₂ in photocrosslinked PVCA film for a capacitive‐type humidity sensor

Abstract

ABSTRACT:The sorption behavior of water vapor and CO 2 gas in photocrosslinked poly(vinyl cinnamate) (PVCA) film was examined at 30°C under atmospheric pressure. Both the water sorption isotherm and the CO 2 sorption isotherm obtained with quartz crystal microbalance (QCM) method obeyed the simple Langmuir's equation. Water vapor/CO 2 mixed-gas sorption isotherms were also obtained. Total amount of sorbed mixed gases was clearly influenced by the partial pressure of water vapor (p w ) and CO 2 gas (p c ) in the atmosphere. A modified Langmuir's equation based on a dual-site model was employed for predicting the competitive adsorption isotherm, and the isotherm was clearly described by the equation. The theoretically estimated amount of adsorbed water at the constant p w decreased slightly with increasing p c . The effect of this phenomenon on the sensitivity of the capacitive-type relative humidity sensor was examined. As expected, the electrical capacitance of the sensor at the constant relative humidity decreased because of the coexistence of CO 2 gas. However, the influence was quite small in the CO 2 concentration range in the ordinary environment.

Addition of α‐tocopherol on poly(lactic acid): Thermal, mechanical, and sorption properties

“…QCM sensors have been successfully used in a variety of applications using standard oscillator techniques and frequency counting. One of them is its applicability in sorption of gases in solid thin films 31–41. In this work, the sorption of oxygen and carbon dioxide in PLA and PLA enriched with α‐tocopherol films was obtained by QCM technique, described in detail in a previous work36 along with its basic operating principle.…”

“…One of them is its applicability in sorption of gases in solid thin films. [31][32][33][34][35][36][37][38][39][40][41] In this work, the sorption of oxygen and carbon dioxide in PLA and PLA enriched with atocopherol films was obtained by QCM technique, described in detail in a previous work 36 along with its basic operating principle. Special care was taken so that the Sauerbray equation 42 is valid, meaning that the added mass was evenly distributed over the electrodes and is much smaller than the weight of the quartz disk, Df/f ( 1.…”

DFT studies for the evaluation of amine functionalized polystyrene adsorbents for selective adsorption of carbon dioxide

“…[8][9][10][11][12][13][14][15] However, the development of low cost adsorbent with high CO 2 selectivity and adequate adsorption capacity under ambient conditions is an active area of research. 16 The solid sorbents such as activated carbon, 17 zeolites, 18 zeolitic imidazole frameworks (ZIFs), 19 single/multi-walled carbon nanotubes, 1 nanoporous silica-based molecular basket, 20 polymers [21][22][23][24][25] and metal-organic frameworks (MOFs) 1,7,10 have been used for adsorption of CO 2 . The recent studies have focused on use of amine functionalized adsorbents for selective separation of CO 2 from ue gas mixtures.…”

“…11 Extensive efforts are being directed from a variety of elds including polymer technology to search better CO 2 capturing materials. [21][22][23][24][25][31][32][33] The surface properties of the polymer can easily be tailored with different organic or inorganic ligands. Aer functionalization of the polymer surface, the accessibility of the amine to capture CO 2 is the most important factor to be considered during adsorption.…”