Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 2 de 2
Filtrar
Más filtros










Base de datos
Intervalo de año de publicación
1.
Polymers (Basel) ; 15(9)2023 Apr 28.
Artículo en Inglés | MEDLINE | ID: mdl-37177254

RESUMEN

Because of the increasing scarcity of water resources, the desalination of seawater by photothermal evaporation with harvested solar energy has gradually become a popular research topic. The interconnected macroporous cryogel prepared from polymerization and crosslinking below the freezing temperature of the reactant solution has an excellent performance in photothermal water evaporation after loading photothermal materials. In this study, polyacrylamide (PAM) cryogels were prepared by cryo-polymerization and sulfonated in an alkaline solution containing formaldehyde and Na2SO3. Importantly, the evaporation enthalpy of water in sulfonated PAM cryogel was reduced to 1187 J·g-1 due to the introduction of sulfonate groups into PAM, which was beneficial to increase the photothermal evaporation rate and efficiency. The sulfonated PAM cryogels loaded with polypyrrole and the umbrella-shaped melamine foam substrate were combined to form a photothermal evaporation device, and the evaporation rate was as high as 2.50 kg·m-2·h-1 under one-sun radiation. Meanwhile, the evaporation rate reached 2.09 kg·m-2·h-1 in the 14 wt% high-concentration saline solution, and no salt crystals appeared on the surface of the cryogel after 5 h of photothermal evaporation. Therefore, it was evidenced that the presence of sulfonate groups not only reduced the evaporation enthalpy of water but also prevented salting-out from blocking the water delivery channel during photothermal evaporation, with a sufficiently high evaporation rate, providing a reliable idea of matrix modification for the design of high-efficiency photothermal evaporation materials.

2.
Gels ; 8(9)2022 Sep 01.
Artículo en Inglés | MEDLINE | ID: mdl-36135268

RESUMEN

The macro-porous structure of polymer cryogels provides an appropriate channel for the adsorption and transport of substances, endowing its application in the field of electrochemical sensing. The combination mode of a polymer matrix and electro-active substance, particularly the distribution of an electro-active substance in the matrix, has an important effect on the overall performance of the sensor. In this work, through the simultaneous oxidation coupling polymerization of aniline (ANI) and radical polymerization of acrylamide (AAm) under cryogenic condition, conductive composite cryogels were prepared, aiming for the uniform distribution of PANI in the PAAm matrix. The possibility of simultaneous polymerizations was symmetrically investigated, and the obtained PANI/PAAm cryogels were characterized. Due to the acid-doping of PANI, the electrical conductivity of PANI/PAAm cryogels could be modulated with acidic and basic gases. Thus, the performance of the gas sensor was studied by making conductive PANI/PAAm cryogel sheets as resistive sensor electrodes. We found that the content of PANI, the sheet thickness and the dry/wet state of the cryogel influenced the response sensitivity and rate as well as the recovery properties. The response duration for HCl and NH3 gas was shorter than 70 and 120 s, respectively. The cyclic detection of HCl gas and the alternate detection of NH3/HCl were achieved. This gas sensor with advantages, including simple preparation, low cost and high sensitivity, would have great potential for the application to monitor the leakage of acidic and basic gases.

SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA