Effect of Fluorene Groups on the Properties of Multiblock Poly(arylene ether sulfone)s-Based Anion-Exchange Membranes

Abstract

Two kinds of novel multiblock poly(arylene ether sulfone)s were synthesized via block copolycondensation of telechelic oligomers as a starting material for the preparation of anion-exchange membranes (AEMs). The as-synthesized copolymers have extremely similar main chains. The difference is that the benzylmethyl groups for one are located on the fluorene-sulfone segments and they are located on the isopropylidene-sulfone segments for the other. The benzylmethyl moieties served as precursors to cationic sites and were brominated using N-bromosuccinimide (NBS) and then quaternized with N,N,N',N'-tetramethyl-1,6-diaminohexane (TMHDA). Controlled bromination and quaternization at specific positions of the benzylmethy-containing fluorene-sulfone segments and isopropylidene-sulfone segments can be achieved. 1H NMR spectroscopy, Fourier transform infrared spectroscopy, and gel permeation chromatography were used to characterize the as-synthesized copolymers. Distinct microphase separation in the as-prepared AEMs was observed using small-angle X-ray scattering and transmission electron microscopy. The AEM containing fluorene-sulfone segments (IEC=1.89 meq·g(-1)) showed higher ionic conductivity and methanol permeability than that containing isopropylidene-sulfone segments (IEC=2.03 meq·g(-1)). Moreover, the former showed better alkaline stability than the latter.

Anion exchange membranes based on carbazole-containing polyolefin for direct methanol fuel cells

“…The mass of the dried OH À form membrane was weighted after drying at 60°C under vacuum for more than 24 h. Then the WU was measured by a quartz spring balance reported in the literature [26]. The water uptake of the membrane can be calculated by Hooke's law:…”

Hybrid anion exchange membranes with self‐assembled ionic channels

“…[2] As a key component, the anion exchange membrane (AEM) is one of the research focuses on AEMFCs owing to the absence of AEMs which meets the requirements for AEMFCs. [3] As a consequence, considerable efforts have been made to develop novel AEMs with high performances and many new AEM materials have been reported, including quaternized poly(ether ether ketone), [4,5] quaternized poly(sulfone), [6][7][8] imidazolium-functionalized poly (ether sulfone), [9] quaternized poly(ether-imide), [10] quaternized polybutadiene-b-poly(4-methylstyrene), [11] quaternized poly(2,6-dimethyl-1,4-phenylene oxide), [12][13][14] quaternized copoly(arylene ether sulfone)s, [15][16][17] quaternized poly(aryl ether oxadiazole), [18] quaternized poly(tetraphenyl ether ketone sulfone), [19] quaternary poly(arylene ether ketone), [20] poly(arylene ether)s containing quaternized ammonio-substituted fluorene groups, [21] quaternary phosphonium-functionalized poly(sulfone), [22] guanidiniumfunctionalized poly(2,6-dimethyl-1,4-phenylene oxide), [23] phenylguanidinium-functionalized perfluorinated polymer, [24] permethyl cobaltocenium functionalized poly(sulfone), [25] modified commercial polymers by introduction of hydrophilic additives, [26][27][28][29][30] grafting, [31,32] reinforcement, [33] and semiinterpenetrating polymer network. [34] Some homogeneous AEMs showed phase-separated, bicontinuous morphologies and well-developed ionic channels through cleverly designed structures.…”

“…[34] Some homogeneous AEMs showed phase-separated, bicontinuous morphologies and well-developed ionic channels through cleverly designed structures. [7,11,12,[15][16][17]19,21] However, scarce organic-inorganic hybrid AEMs showed well-controlled morphologies and ionic channels due to the absence of effective methodology for adjusting them. In this study, we proposed a strategy to control the morphologies and ionic channels in organic-inorganic AEMs by in situ self-assembly technology ( Figure 1).…”

Novel hydrophilic-hydrophobic block copolymer based on cardo poly(arylene ether sulfone)s with bis-quaternary ammonium moieties for anion exchange membranes

“…Anion exchange membranes (AEMs), the critical component of AMFCs to transport hydroxide ions from the cathode to the anode, have been rapidly developed over the past decade. To date, the design of AEMs materials in AMFCs has mainly focused on quaternary ammonium, quaternary phosphonium or guanidinium functionalized polymers, such as poly(arylene ether sulfone) [5][6][7], poly(arylene ether ketone) [8][9][10], poly(arylene ether)s [11,12], poly(phenylene oxide)s [13][14][15] and poly(phenylene)s [16,17]. The primary challenge 3 to realize the commercialization of AEMs is to prepare membrane materials with adequate mechanical strength, superior ionic conductivity and necessary stability under alkaline fuel cells operating conditions.…”

“…Both of copolymers 5 were grated with bis-quaternary ammonium groups in a certain length for aliphatic side chains to improve the density and flexibility of hydrophilic ionic segments. The corresponding anion exchange membranes based on these two copolymers were prepared and ion conductivity, mechanical properties, water uptake, swelling ratio, morphology as well as alkaline stability were investigated.…”