Two series of disulfonated iptycene-based poly(arylene ether sulfone) random copolymers, i.e., TRP-BP (triptycene-based) and PENT-BP (pentiptycene-based), were synthesized via condensation polymerization from disulfonated monomer and comonomers to prepare proton exchange membranes (PEMs) for potential applications in electrochemical devices such as fuel cell. To investigate the effect of iptycene units on membrane performance, these copolymers were systematically varied in composition (i.e., iptycene content) and the degree of sulfonation (i.e., 30-50%), which were characterized comprehensively in terms of water uptake, swelling ratio, oxidative stability, thermal and mechanical properties, and proton conductivity at various temperatures. Comparing to copolymers without iptycene units, TRP-BP and PENT-BP ionomers showed greatly enhanced thermal and oxidative stabilities due to strong intra- and inter-molecular supramolecular interactions induced by hierarchical iptycene units. In addition, the introduction of iptycene units in general provides PEMs with exceptional dimensional stability of low volume swelling ratio at high water uptakes, which is ascribed to the supramolecularly interlocked structure as well as high fractional free volume of iptycene-based polymers. It is demonstrated that the combination of high proton conductivity and good membrane dimension stability is the result of the synergistic effects of multiple factors including free volume (iptycene content), sulfonation degree, hydrophobicity, and swelling behavior (supramolecular interactions).
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http://dx.doi.org/10.3389/fchem.2020.00674 | DOI Listing |
Chemistry
February 2024
Institute for Materials Chemistry and Engineering, Kyushu University, 6-1 Kasugako-en, Kasuga, 816-8580, Japan.
Invited for the cover of this issue is the group of Takayuki Iwata and Mitsuru Shindo at Kyushu University. The image depicts the longest-chain iptycene synthesized in this study, showing the connections between iptycene synthetic units by using transparent cases. Read the full text of the article at 10.
View Article and Find Full Text PDFChempluschem
April 2021
Institute of condensed matter and nanosciences (IMCN), Molecular Chemistry, Materials and Catalysis (MOST), Place Louis Pasteur 1/L4.01.02, 348, Louvain-la-Neuve, Belgium.
Diversification of the structures and the applications possible for foldamers rely on expansion of the building block library available for their synthesis. In this work, we describe the synthesis of a range of three dimensional heteroaromatic monomers, based on iptycene scaffolds, that are suitable for the synthesis of aromatic oligoamide foldamers. These units can be obtained in gram quantities in up to 80 % yield through [4+2] cycloaddition between diester, diamine, and amino acid derivatives of 1,8-diazaanthracenes and a variety of dienophiles.
View Article and Find Full Text PDFFront Chem
August 2020
Department of Chemical and Biomolecular Engineering, University of Notre Dame, Notre Dame, IN, United States.
Two series of disulfonated iptycene-based poly(arylene ether sulfone) random copolymers, i.e., TRP-BP (triptycene-based) and PENT-BP (pentiptycene-based), were synthesized via condensation polymerization from disulfonated monomer and comonomers to prepare proton exchange membranes (PEMs) for potential applications in electrochemical devices such as fuel cell.
View Article and Find Full Text PDFChemistry
December 2019
Division of Materials Science, Nara Institute of Science and Technology, 8916-5 Takayama-cho, Ikoma, 630-0192, Japan.
Substituted acene derivatives are regarded as promising materials for organic electronic devices such as organic light-emitting diodes (OLEDs). In particular, anthracene derivatives are known to exhibit good fluorescence property, with the air stability and solubility in common organic solvents expected to give advantages for solution-processed device fabrication. In this study, a series of bistriisopropylsilyl(TIPS)ethynyl anthracene derivatives with azaacene-containing iptycene wings have been synthesized by using condensation reactions.
View Article and Find Full Text PDFChemistry
November 2014
Department of Chemistry, National Taiwan University, No. 1, Sec. 4, Roosevelt Rd., Taipei (Taiwan).
Dependence of the backbone planarity of oligo(p-phenyleneethynylene)s (OPEs) on the intrinsic electronic character of substituents and on the nature of the solvent has been experimentally demonstrated with a series of center-symmetrical five-ring systems, pentiptycene-pentiptycene-arene-pentiptycene-pentiptycene, differing in the substituents on the central arene. In frozen 2-methyltetrahydrofuran (MTHF), the adjacent pentiptycene units prefer to be in a mutually twisted orientation when the substituents are electron-withdrawing (F and amido), resulting in a TPPT or TTTT conformation, whereas a planarized PPPP backbone is favored in the case of electron-donating substituents (alkyl and alkoxy). The propensity to adopt the PPPP form is generally enhanced by replacing MTHF with either methylcyclohexane or mixed ethanol/methanol as solvent.
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