Self-healing polymeric materials for membrane separation: an example of a polybenzimidazole-based membrane for pervaporation dehydration on isopropanol aqueous solution

Abstract

The demonstration of a self-healing material based separation membrane for pervaporation dehydration on liquid–liquid mixtures.

From polybenzimidazoles to polybenzimidazoliums and polybenzimidazolides

“…178 The approach has been used for the preparation N-alkylated m-PBI as an effective method to improve organosolubility, [179][180][181][182] to provide plasticity, and to enhance the free volume in the solid state. 86,183 Furthermore, the method renders a pathway to PBIs containing rotaxanes in the form of permethyl-β-cyclodextrin(s), 179 crown ethers, 184 furan, 35 organosilanes, 182 or ion exchange functionalities. 185,186 The method can also be used for alkylsulfonation employing e.g.…”

“…Controlled crosslinking can be carried out by co-casting the polybenzimidazole from an organic solvent containing the bifunctional halomethyl electrophile and initiating the N-substitution in the solid state at elevated temperatures. The method has been utilized to produce crosslinked m-PBI with a wide range of crosslinking agents such as α,α´-dichloro-p-xylene (and derivatives thereof), 36,200 α,α´-dibromo-p-xylene, 201 1,12-diiodododecane, 202 1,3,5-tris(bromomethyl)benzene, 203,204 dichloromethyl phosphinic acid, 205 bismaleimide 35 and silanes. 206 Alternatively, m-PBI can be crosslinked in a heterogeneous process where the polymer film is immersed in a solution containing the crosslinking agent.…”

“…Furthermore, derivatives of PBI are emerging as promising base materials for various demanding gas- [30][31][32][33][34] and liquid 35,36 The inherent functionality of the PBIs stems from the amphoteric nature of the benzimidazole groups. They react according to fundamental Brønsted acid-base chemistry to form cationic ionenes as protic polybenzimidazoliums in acidic environment or anionic ionenes as polybenzimidazolides under alkaline conditions.…”

Surface Properties, Free Volume, and Performance for Thin-Film Composite Pervaporation Membranes Fabricated through Interfacial Polymerization Involving Different Organic Solvents

“…There is a larger driving force at high temperature, resulting in high permeation flux. However, there is also movement and enlargement of polymer chain, while the mobility of the water and alcohol was boosted, hence, more alcohol could penetrate through the membrane, resulting in water concentration in permeate decreased from 99.2 ± 1.7 to 91.5 ± 0.3 wt% [ 38 ].…”

Stimuli responsive self-healing polymers: gels, elastomers and membranes

“…The Diels-Alders (DA) reaction is one of the most dominant synthetic strategies for the development of thermally healable materials as it is synthetically accessible and versatile (it can be combined with various monomer synthons), it does not require the presence of catalysts other than temperature to drive the equilibrium of the reaction and it exhibits adequate tolerance towards oxygen. [18][19][20] In addition, the DA reaction is a selfcontained system in that the number of atoms of the reactants and the products is constant (unlike for example, in condensation processes), which simplifies significantly the reaction conditions, and the problem of volume change of the bulk material during healing/remending is relatively limited. In a seminal paper, Wudl et al presented a novel, two-component, re-mendable polymeric material comprising a 4-arm furan capped precursor that could be readily polymerized with a 3-arm maleimide synthon via a thermally triggered DA type of crosslinking.…”