Sensing carbon dioxide through a solution transparency change in gas-responsive polymers

摘要: The use of thermosensitive polymers exhibiting an upper critical solution temperature (UCST) for sensing and detecting the presence CO2 in aqueous was demonstrated. By synthesizing random copolymers acrylamide (AAm), acrylonitrile (AN) N,N-diethylaminoethyl methacrylate (DEAEMA), which have different relative contents AAm AN but a similar small amount CO2-responsive DEAEMA (below 3%), two means monitoring concentration through transparency change polymer sensor were investigated. On one hand, using single P(AAm-co-AN-co-DEAEMA) copolymer whose phase transition-induced transmittance upon cooling is completed within narrow range cloud point (CP) sensitively decreased increasing CO2, at given (25 °C) allows threshold to be detected by showing abrupt transmittance. other mixing with largely CPs (over 30 K), sharp UCST-type transition suppressed; instead proceeds slowly gradually over wide region (>35 K). mixed can used monitor increase gradual mostly linear changes Both observed naked eye.