Protic acid-induced LCST rigid-chain polymeric gel with enhanced blue emission via weakened conjugation effect

Tang, Siyi; Ye, Xinhe; Gao, Yingxin; Xu, Ruopei; Luo, Longbo; Li, Xiangyang

doi:10.1016/j.eurpolymj.2021.110333

Cited by 5 publications

(1 citation statement)

References 37 publications

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“…In addition, the polymer with the larger void free-volume has the longer long-lifetime, and the relative peak intensity ( I 3 ) is proportional to the number of voids. f represents the relative free-volume content within the membrane matrix. ,− Figure b shows the free-volume distribution. Therein, we can see that δ 3 of 12A-PAES-sIM is 2009 ps and δ 3 of IM-PAES-sIM is 2014 ps, which are in accordance with the average void free-volumes in 12A-PAES-sIM and IM-PAES-sIM of about 88 and 101 Å 3 , respectively.…”

Section: Results and Discussionmentioning

confidence: 99%

Subnanometer Ion Channel Anion Exchange Membranes Having a Rigid Benzimidazole Structure for Selective Anion Separation

et al. 2022

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Ion-conductive polymers having a well-defined phase-separated structure show the potential application of separating mono- and bivalent ion separation. In this work, three side-chain-type poly(arylene ether sulfone)-based anion exchange membranes (AEMs) have been fabricated to investigate the effect of the stiffness of the polymer backbone within AEMs on the Cl–/NO3 – and Cl–/SO4 2– separation performance. Our investigations via small-angle X-ray scattering (SAXS), positron annihilation, and differential scanning calorimetry (DSC) demonstrate that the as-prepared AEM with a rigid benzimidazole structure in the backbone bears subnanometer ion channels resulting from the arrangement of the rigid polymer backbone. In particular, SAXS results demonstrate that the rigid benzimidazole-containing AEM in the wet state has an ion cluster size of 0.548 nm, which is smaller than that of an AEM with alkyl segments in the backbone (0.760 nm). Thus, in the electrodialysis (ED) process, the former exhibits a superior capacity of separating Cl–/SO4 2– ions relative to latter. Nevertheless, the benzimidazole-containing AEM shows an inability to separate the Cl–/NO3 – ions, which is possibly due to the similar ion size of the two. The higher rotational energy barrier (4.3 × 10–3 Hartree) of benzimidazole units and the smaller polymer matrix free-volume (0.636%) in the AEM significantly contribute to the construction of smaller ion channels. As a result, it is believed that the rigid benzimidazole structure of this kind is a benefit to the construction of stable subnanometer ion channels in the AEM that can selectively separate ions with different sizes.

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