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1. High‐Temperature and High‐Energy‐Density Dipolar Glass Polymers Based on Sulfonylated Poly(2,6‐dimethyl‐1,4‐phenylene oxide)

   https://doi.org/10.1002/anie.201710474  

   Zhang, Zhongbo ; Wang, David H. ; Litt, Morton H. ; Tan, Loon‐Seng ; Zhu, Lei ( January 2018 , Angewandte Chemie International Edition)

   A new class of high‐temperature dipolar polymers based on sulfonylated poly(2,6‐dimethyl‐1,4‐phenylene oxide) (SO₂‐PPO) was synthesized by post‐polymer functionalization. Owing to the efficient rotation of highly polar methylsulfonyl side groups below the glass transition temperature (T_g≈220 °C), the dipolar polarization of these SO₂‐PPOs was enhanced, and thus the dielectric constant was high. Consequently, the discharge energy density reached up to 22 J cm⁻³. Owing to its highT_g , the SO₂‐PPO₂₅sample also exhibited a low dielectric loss. For example, the dissipation factor (tan δ) was 0.003, and the discharge efficiency at 800 MV m⁻¹was 92 %. Therefore, these dipolar glass polymers are promising for high‐temperature, high‐energy‐density, and low‐loss electrical energy storage applications.

    

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2. High‐Temperature and High‐Energy‐Density Dipolar Glass Polymers Based on Sulfonylated Poly(2,6‐dimethyl‐1,4‐phenylene oxide)

   https://doi.org/10.1002/ange.201710474  

   Zhang, Zhongbo ; Wang, David H. ; Litt, Morton H. ; Tan, Loon‐Seng ; Zhu, Lei ( January 2018 , Angewandte Chemie)

   A new class of high‐temperature dipolar polymers based on sulfonylated poly(2,6‐dimethyl‐1,4‐phenylene oxide) (SO₂‐PPO) was synthesized by post‐polymer functionalization. Owing to the efficient rotation of highly polar methylsulfonyl side groups below the glass transition temperature (T_g≈220 °C), the dipolar polarization of these SO₂‐PPOs was enhanced, and thus the dielectric constant was high. Consequently, the discharge energy density reached up to 22 J cm⁻³. Owing to its highT_g , the SO₂‐PPO₂₅sample also exhibited a low dielectric loss. For example, the dissipation factor (tan δ) was 0.003, and the discharge efficiency at 800 MV m⁻¹was 92 %. Therefore, these dipolar glass polymers are promising for high‐temperature, high‐energy‐density, and low‐loss electrical energy storage applications.

    

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3. High transconductance and current density in field effect transistors using arrays of bundled semiconducting carbon nanotubes

   https://doi.org/10.1063/5.0093859  

   Foradori, Sean M. ; Dwyer, Jonathan H. ; Suresh, Anjali ; Gopalan, Padma ; Arnold, Michael S. ( August 2022 , Applied Physics Letters)

   We examine if the bundling of semiconducting carbon nanotubes (CNTs) can increase the transconductance and on-state current density of field effect transistors (FETs) made from arrays of aligned, polymer-wrapped CNTs. Arrays with packing density ranging from 20 to 50 bundles  μm −1 are created via tangential flow interfacial self-assembly, and the transconductance and saturated on-state current density of FETs with either (i) strong ionic gel gates or (ii) weak 15 nm SiO 2 back gates are measured vs the degree of bundling. Both transconductance and on-state current significantly increase as median bundle height increases from 2 to 4 nm, but only when the strongly coupled ionic gel gate is used. Such devices tested at −0.6 V drain voltage achieve transconductance as high as 50 μS per bundle and 2 mS  μm −1 and on-state current as high as 1.7 mA  μm −1 . At low drain voltages, the off-current also increases with bundling, but on/off ratios of ∼10 5 are still possible if the largest (95th percentile) bundles in an array are limited to ∼5 nm in size. Radio frequency devices with strong, wraparound dielectric gates may benefit from increased device performance by using moderately bundled as opposed to individualized CNTs in arrays. 

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4. Textured Poling of the Ferroelectric Dielectric Layer for Improved Organic Field‐Effect Transistors

   https://doi.org/10.1002/admi.201801787  

   Laudari, Amrit ; Pickett, Alec ; Shahedipour‐Sandvik, Fatemeh ; Hogan, Kasey ; Anthony, John E. ; He, Xiaoqing ; Guha, Suchismita ( January 2019 , Advanced Materials Interfaces)

   Polymer ferroelectrics are playing an increasingly active role in flexible memory application and wearable electronics. The relaxor ferroelectric dielectric, poly(vinylidene fluoride trifluorethylene (PVDF‐TrFE), although vastly used in organic field‐effect transistors (FETs), has issues with gate leakage current especially when the film thickness is below 500 nm. This work demonstrates a novel method of selective poling the dielectric layer. By using solution‐processed 6,13‐bis(triisopropylsilylethynyl)pentacene (TIPS‐pentacene) as the organic semiconductor, it is shown that textured poling of the PVDF‐TrFE layer dramatically improves FET properties compared to unpoled or uniformly poled ferroelectric films. The texturing is achieved by first vertically poling the PVDF‐TrFE film and then laterally poling the dielectric layer close to the gate electrode. TIPS‐pentacene FETs show on/off ratios of 10⁵and hole mobilities of 1 cm²Vs⁻¹under ambient conditions with operating voltages well below −5 V. The electric field distribution in the dielectric layer is simulated by using finite difference time domain methods.

    

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5. Pentiptycene-based ladder polymers with configurational free volume for enhanced gas separation performance and physical aging resistance

   https://doi.org/10.1073/pnas.2022204118  

   Corrado, Tanner J. ; Huang, Zihan ; Huang, Dezhao ; Wamble, Noah ; Luo, Tengfei ; Guo, Ruilan ( September 2021 , Proceedings of the National Academy of Sciences)

   Polymers of intrinsic microporosity (PIMs) have shown promise in pushing the limits of gas separation membranes, recently redefining upper bounds for a variety of gas pair separations. However, many of these membranes still suffer from reductions in permeability over time, removing the primary advantage of this class of polymer. In this work, a series of pentiptycene-based PIMs incorporated into copolymers with PIM-1 are examined to identify fundamental structure–property relationships between the configuration of the pentiptycene backbone and its accompanying linear or branched substituent group. The incorporation of pentiptycene provides a route to instill a more permanent, configuration-based free volume, resistant to physical aging via traditional collapse of conformation-based free volume. PPIM-ip-C and PPIM-np-S, copolymers with C- and S-shape backbones and branched isopropoxy and linearn-propoxy substituent groups, respectively, each exhibited initial separation performance enhancements relative to PIM-1. Additionally, aging-enhanced gas permeabilities were observed, a stark departure from the typical permeability losses pure PIM-1 experiences with aging. Mixed-gas separation data showed enhanced CO₂/CH₄selectivity relative to the pure-gas permeation results, with only ∼20% decreases in selectivity when moving from a CO₂partial pressure of ∼2.4 to ∼7.1 atm (atmospheric pressure) when utilizing a mixed-gas CO₂/CH₄feed stream. These results highlight the potential of pentiptycene’s intrinsic, configurational free volume for simultaneously delivering size-sieving above the 2008 upper bound, along with exceptional resistance to physical aging that often plagues high free volume PIMs.

    

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