Ion-containing block copolymers continue to attract significant interest as conducting membranes in energy storage devices. Reversible addition−fragmentation chain transfer (RAFT) polymerization enables the synthesis of well-defined ionomeric A−BC−A triblock copolymers, featuring a microphase-separated morphology and a combination of excellent mechanical properties and high ion transport. The soft central "BC" block is composed of poly(4-styrenesulfonyl-(trifluoromethylsulfonyl)imide) (poly(Sty-Tf 2 N)) with −SO 2 −N − −SO 2 −CF 3 anionic groups associated with a mobile lithium cation and low-T g di(ethylene glycol)methyl ether methacrylate (DEGMEMA) units. External polystyrene A blocks provide mechanical strength with nanoscale morphology even at high ion content. Electrochemical impedance spectroscopy (EIS) and pulse-field-gradient (PFG) NMR spectroscopy have clarified the ion transport properties of these ionomeric A−BC−A triblock copolymers. Results confirmed that well-defined ionomeric A−BC−A triblock copolymers combine improved ion-transport properties with mechanical stability with significant potential for application in energy storage devices.

Photopolymerization coupled with mask projection microstereolithography successfully generated various 3D printed phosphonium polymerized ionic liquids (PILs) with low UV light intensity requirements and high digital resolution. Varying phosphonium monomer concentration, diacrylate cross-linking comonomer, and display images enabled precise 3D design and polymeric properties. The resulting cross-linked phosphonium PIL objects exhibited a synergy of high thermal stability, tunable glass transition temperature, optical clarity, and ion conductivity, which are collectively well-suited for emerging electro-active membrane technologies. Ion conductivity measurements on printed objects revealed a systematic progression in conductivity with ionic liquid monomer content, and thermal properties and solvent extraction demonstrated the formation of a polymerized ionic liquid network, with gel fractions exceeding 95%.

Nitroxide-mediated polymerization (NMP) affords the synthesis of well-defi ned ABA triblock copolymers with polystyrene external blocks and a charged poly(1-methyl-3-(4-vinylbenzyl)-imidazolium bis(trifl uoromethane sulfonyl)imide central block. Aqueous size-exclusion chromatography (SEC) and 1 H NMR spectroscopy studies confi rm the control of the composition and block lengths for both the central and external blocks. Dynamic mechanical analysis (DMA) reveals a room temperature modulus suitable for fabricating these triblock copolymers into electroactive devices in the presence of an added ionic liquid. Dielectric relaxation spectroscopy (DRS) elucidates the ion-transport properties of the ABA triblock copolymers with varied compositions. The ionic conductivity in these single-ion conductors exhibits Vogel-FulcherTammann (VFT) and Arrhenius temperature dependences, and electrode polarization (EP) analysis determines the number density of simultaneously conducting ions and their mobility. The actuators derived from these triblock copolymer membranes experience similar actuation speeds at an applied voltage of 4 V DC, as compared with benchmark Nafi on membranes. These tailorable ABA block copolymers are promising candidates for ionic-polymer device applications.