Epoxides are a promising polymer materials platform because of their diverse functionality, ease of synthesis, availability, and ring strain favoring polymerization. Recently reported mono(μ-alkoxo)bis(alkylaluminum) (MOB) based polymerization technique provides controlled molecular weight polymers for wide variety of functional epoxides without chain transfer. We want to use this facile polymerization platform to create polymers with orthogonally addressable pendant groups to precisely tune polymer properties. Specifically, this work focuses on incorporation of charged moieties through post polymerization modification of functional pendent groups to investigate their transport and self-assembly properties. We have demonstrated control over molecular weight, composition, and architecture via copolymerization of propargyl glycidyl ether (PGE) and epichlorohydrin (ECH), with functional alkyne and chloromethyl groups respectively. Molecular weights up to 100 kg/mol with narrow distributions were achieved. Copolymer composition was varied by incorporating increasing ratios of PGE (20-80%) in the polymerization feed. In situ 1H NMR kinetic study was performed using two different systems that is MOB and separate initiator-catalyst to determine reactivity ratios. With the use of Meyer-Lowry method reactivity ratios were calculated as rPGE = 0.69 and rECH = 1.43 for MOB system, and rPGE= 0.72 and rECH= 1.48 for separate initiator-catalyst system. So, in both cases rPGE×rECH ≈1 which confirms the statistical nature of the copolymer with preferred addition of ECH to growing chain end regardless of polymerization technique. These precursor copolymers were further modified with various charged groups such as imidazole and sulfonate via orthogonal chemistry through the chloromethyl and alkyne moieties. This will be beneficial in achieving tuned compositional control of structure–property relationships in a polyether materials platform. These functional polyethers were then used to create economical crosslinked networks to prepare amphoteric ion exchange membranes (AIEMs). Nafion ion exchange membranes have been used in vanadium redox flow batteries (VRFB) applications owing to their good ionic conductivity and excellent chemical and mechanical stability. But nafion’s high cost, excessive swelling and low ion selectivity limits its use for commercialization. AIEMs have potential for preventing vanadium ion penetration thus increasing ion selectivity. Membranes were synthesized by grafting of novel ECH and PGE-based charged copolymer S-P(PGE-stat-ECH) to the PVDF-co-HFP membrane matrix. We studied the physicochemical, electrochemical, and surface properties of these membranes to investigate candidacy of this novel membrane for VRFB application. Next, we used a homopolymer of allyl glycidyl ether (PAGE) as a unifying platform for polyelectrolyte design. With the use of click chemistry we created polyether based polyanions and polycations to study effect of charge and molecular weight on self-assembly. We studied effect of NaCl and LiCl salt as well on polyelectrolyte self-assembly with varying polyanions to polycation ratios. Coacervation formations was studied using absorbance measurements on UV-vis spectrophotometer. With the use of MOB polymerization platform, we can synthesize variety of polymers, and this will be useful in exploring effects of counter-ions, polymer architecture, charge densities in future. Our synthetic platform provides control over different governing parameters separately which will be impactful in giving insights on polyelectrolyte self-assembly from fundamental standpoint. We expect the broader impacts of this research to encompass innovation in polyelectrolyte design and application. In conclusion, we demonstrated control over factors such as molecular weight, polymer architecture, charge density, monomer sequence, and counter-ions independently with the use of this platform. We have utilized these materials to further develop AIEMs for electrochemical application and to study charged polymer self-assembly.
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