abstract
This work proposes the use of triblock copolymers as structurally versatile constituents to develop double stimuli -responsive aqueous biphasic systems (ABS) comprising ionic liquids (ILs). Phase diagrams of ABS comprising cholinium acetate ([Ch][C2O2]) and triblock copolymers composed of polyethylene oxide (PEO) and poly-propylene oxide (PPO) with adjustable compositions of PEO, 20% (PE 6200) and 40% (PE 6400), were deter-mined by the cloud point titration method at several temperatures (25-45 degrees C) and pH (5-7). These ABS present, for all the tested pH conditions, a Lower Critical Solution Temperature (LCST)-like behavior. However, only ABS with PE 6400 copolymer exhibit a simultaneous response to both stimuli. Compared to the homologous ho-mopolymer polypropylene glycol (PPG), and despite their lower capacity to form ABS, copolymers with an adequate content of PEO provide a stronger response to the simultaneous action of pH and temperature. The results obtained highlight the value of an appropriate adjustment of the polymer structure/monomer composi-tion in the development of ABS with double response to temperature and pH. The enhanced tailoring ability of the proposed systems is demonstrated with the simultaneous separation of two dyes by the application of the studied stimuli.
keywords
2-PHASE SYSTEMS; POLYETHYLENE-GLYCOL; PROTEIN SEPARATION; EQUILIBRIUM; EXTRACTION; PH
subject category
Engineering
authors
Rufino, AFCS; Ribeiro, SC; Coutinho, JAP; Silva, FA; Freire, MG
our authors
Ana Francisca Osório de Almeida Coelho e Silva
Junior Researcher
Mara Guadalupe Freire Martins
Coordinating ResearcherGroups
G4 - Renewable Materials and Circular Economy
G5 - Biomimetic, Biological and Living Materials
Projects
CICECO - Aveiro Institute of Materials (UIDB/50011/2020)
CICECO - Aveiro Institute of Materials (UIDP/50011/2020)
Associated Laboratory CICECO-Aveiro Institute of Materials (LA/P/0006/2020)
acknowledgements
This work was developed within the scope of the project CICECO- Aveiro Institute of Materials, UIDB/50011/2020, UIDP/50011/2020 and LA/P/0006/2020, financed by national funds through the FCT/MEC (PIDDAC) . This work was developed within the project EXPL/BII-BTI/0731/2021, financed by national funds (OE) , through FCT/MCTES. A. F.C.S. Rufino and F.A. e Silva acknowledge FCT for the PhD grant SFRH/BD/138997/2018 and for the researcher contract CEECIND/03076/2018 under the Scientific Employment Stimulus-Individual Call 2018, respectively.