title: Reversible absorption of CO2 triggered by phase transition of amine-containing micro- and nanogel particles.
abstract: Herein we report that an aqueous solution of temperature-responsive micro- and nanogel particles (GPs) consisting of N-isopropylacrylamide (NIPAm) and N-[3-(dimethylamino)propyl]methacrylamide (DMAPM) reversibly absorbs and desorbs CO(2) via a phase transition induced by cooling and heating cycles (30-75 °C). Below the phase-transition temperature, most of the amines in the swollen GPs are capable of forming ion pairs with absorbed bicarbonate ions. However, above the phase-transition temperature, shrinkage of the GPs lowers the pK(a) and the number of amine groups exposed to water, thereby resulting in almost complete desorption of CO(2). The GPs can reversibly absorb more than the DMAPM monomer and polymer without NIPAm, which indicates the importance of the temperature-responsive phase transition of polymers in determining the degree of absorption. The results show the potential of temperature-responsive polymer solutions as absorbents to sequester CO(2) at a low energy cost.
authors.affiliation: Department of Chemical Engineering, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan. yhoshino@chem-eng.kyushu-u.ac.jp
authors.forename: Yu
authors.initials: Y
authors.lastname: Hoshino
authors.forename: Kazushi
authors.initials: K
authors.lastname: Imamura
authors.forename: Mengchen
authors.initials: M
authors.lastname: Yue
authors.forename: Gen
authors.initials: G
authors.lastname: Inoue
authors.forename: Yoshiko
authors.initials: Y
authors.lastname: Miura