Elastic free-standing RTIL composite membranes for CO2/N2 separation based on sphere-forming triblock/diblock copolymer blends

Abstract

Solvent-free,melt-state self-assembly of sphere-formingpolystyrene-b-poly(ethylene oxide) diblock copolymer/polystyrene-b-poly(ethylene oxide)-b-polystyrene triblock copolymer (SO/SOS) blends has been used to produce free-standing,roomtemperature ionic liquid (RTIL) composite membranes with excellent mechanical properties and CO 2 /N 2 separation performance. Membranes were prepared from vitrified SO/SOS diblock/triblock meltsby swellingwithgreater than 94 wt% 1-ethyl-3-methylimidazoliumbis(trifluoromethylsulfonyl)imide ([EMIM][TFSI]) ionic liquid. Thesefree-standingcomposite membranes were evaluated for their CO 2 /N 2 separation performance over a range of transmembrane pressures,with resultstraversingthe 2008 Robeson upper bound.Even with such high loadings of neat [EMIM][TFSI], these membranes exhibit the mechanical properties of solid elastomers, evident by the

Poly(vinylimidazole-co-butyl acrylate) membranes for CO2 separation

“…[7] Therefore, it is attractive to combine RTILs with membrane technology, which presents advantages of lower energy costs, reduced volatility and easy reuse, to overcome the disadvantages of RTILs. [8] [9] RTILs, especially imidazole based RTILs, possess better solubility to CO 2 than other light gases, such as N 2 and CH 4 . [10] Therefore, RTILs have been widely exploited to separate CO 2 from natural gas and flue gas over the past two decades.…”

Melt-Fabricated Photoreactive Block Copolymer Micelles as Building Blocks for Tunable Elastomeric Hydrogels

“…That is, this narrowing is not likely a product of actual changes in the number of chains per micelle aggregate. This would be consistent with the vitreous nature of the polystyrene cores, long-term shape preservation previously observed in our TPE hydrogel systems, − , and the demonstrated nonergodicity of BCP micelles, all of which suggest room temperature chain exchange among micelles is essentially nonexistent over this time scale. Additionally, SEC measurements confirmed the absence of chain degradation over the 9 week period, although a small amount (<5%) of photocoupling was detected by week nine (Figure S6).…”

Nanostructure-Driven Replication of Soft Tissue Biomechanics in a Thermoplastic Elastomer Hydrogel

“…As shown in Figure , we use melt blends of AB diblock and ABA triblock copolymers, synthetically designed with average block molecular weights ( M n,A or M n,B ), dispersity indices ( Đ ), and volume fractions ( f A or f B ) that favor formation of the classic block copolymer sphere morphology upon heating , to produce a physically cross-linked network of tethered micelle-like units. During melt-state self-assembly, A blocks form spherical aggregates composed of hundreds of chains, while the B blocks form a coronal brush layer which behaves as a matrix in which the spherical A domains reside. − Hydrogel fabrication entails heating the blend to induce self-assembly, vitrifying the sample to trap the developed morphology, and the selectively swelling the B blocks through submersion in aqueous media. Each bridging ABA triblock copolymer thus functions as a tether, mechanically linking adjacent spherical domains.…”