Aniagbaoso Kingsley Ikenna, Król Monika, Ruokolainen Janne, Bousquet Antoine, Save Maud, Rubatat Laurent
Universite de Pau et des Pays de l'Adour, E2S UPPA, CNRS, IPREM, Pau 64053, France.
Department of Applied Physics, School of Science, Aalto University, Espoo FIN 00076, Finland.
ACS Appl Mater Interfaces. 2023 Mar 29;15(12):15998-16008. doi: 10.1021/acsami.2c22766. Epub 2023 Mar 20.
Star block copolymer electrolytes with a lithium-ion conducting phase are investigated in the present work to assess the influence of this complex architecture compared to that of the linear one, on both, bulk morphology and ionic conductivity. For that purpose, the controlled synthesis of a series of poly(styrene--benzyl methacrylate)--poly[oligo(ethylene glycol) methyl ether acrylate] [P(S--BzMA)--POEGA] block copolymers (BCPs) by reversible addition-fragmentation transfer polymerization was performed from either a monofunctional or a tetrafunctional chain transfer agent containing trithiocarbonate groups. We emphasized how a small amount of styrene (6 mol %) drastically improved the control of the RAFT polymerization of benzyl methacrylate mediated by the tetrafunctional chain transfer agent. Transmission electron microscopy and small-angle X-ray scattering demonstrated a clear segregation of the BCPs in the presence of lithium salt. Interestingly, the star BCPs gave rise to highly ordered lamellar structures as compared to that of the linear analogues. Consequently, the reduced lamellae tortuosity of self-assembled star BCPs improved the lithium conductivity by more than 8 times at 30 °C for ∼30 wt % of the POEGA conductive phase.
在本工作中，对具有锂离子传导相的星形嵌段共聚物电解质进行了研究，以评估这种复杂结构与线性结构相比，对本体形态和离子电导率的影响。为此，通过可逆加成-断裂链转移聚合，从含三硫代碳酸酯基团的单官能或四官能链转移剂出发，对一系列聚（苯乙烯-甲基丙烯酸苄酯）-聚[低聚（乙二醇）甲基醚丙烯酸酯][P(S-BzMA)-POEGA]嵌段共聚物（BCP）进行了可控合成。我们强调了少量苯乙烯（6摩尔%）如何极大地改善了由四官能链转移剂介导的甲基丙烯酸苄酯的可逆加成-断裂链转移聚合的控制。透射电子显微镜和小角X射线散射表明，在锂盐存在下，BCP发生了明显的相分离。有趣的是，与线性类似物相比，星形BCP产生了高度有序的层状结构。因此，对于约30 wt%的POEGA导电相，自组装星形BCP降低的片层曲折度在30℃时将锂电导率提高了8倍以上。
