Characterization of carbon dioxide separation membrane with polycation nano-layers

Ultrathin layers of positively charged poly(diallyl dimethylammonium) choloride (PDDA) and negatively charged poly(sodium 4-styrenesulfonate) (PSS) were deposited on SiO2/ polyethylene glycol hybrid membranes via layer-by-layer assembly technique, and carbon dioxide absorption/separation properties were investigated. Quartz crystal microbalance (QCM) measurements revealed that both PDDA and PSS nanocoatings have a good affinity for CO2 absorption. PDDA-deposited film shows about two times higher CO2 ideal gas selectivity compared with unmodified silica film.