Yahata Yoshikazu, Kimura Keiji, Nakanishi Yohei, Marukane Shoko, Sato Takaya, Tsujii Yoshinobu, Ohno Kohji
Institute for Chemical Research , Kyoto University , Gokasho, Uji, Kyoto 611-0011 , Japan.
Department of Material Engineering , Tsuruoka National College of Technology , 104 Sawada, Inooka , Tsuruoka 997-8511 , Japan.
Langmuir. 2019 Mar 12;35(10):3733-3747. doi: 10.1021/acs.langmuir.8b03891. Epub 2019 Mar 3.
Immiscible composite materials with controlled phase-separated structures are important in areas ranging from catalysis to battery. We succeeded in controlling the phase-separated structures of immiscible blends of polystyrene (PS) and two ionic liquids (ILs), namely, N, N-diethyl- N-(2-methoxyethyl)- N-methylammonium bis(trifluoromethylsulfonyl)imide (DEME-TFSI) and 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, by adding precisely designed concentrated polymer brush-grafted (CPB-grafted) silica nanoparticles (CPB-SiPs) prepared by surface-initiated atom-transfer radical polymerization. We discuss relationships between chemical species and molecular weights of the CPB and phase-separated structures. When the CPB was composed of a PS homopolymer of an appropriate molecular weight, the IL phase formed a continuous structure and a quasi-solid-blended film was successfully fabricated because the CPB-SiPs were adsorbed at the PS/IL interface and prevented macroscopic phase separation. We propose that CPB-SiP adsorption and the fabrication of quasi-solid films are governed by the degree of penetration of the matrix PS chains into the CPB and deformability of the CPB-SiPs. We found that the DEME-TFSI domain size can be controlled by the CPB-SiP content and that only 1 wt % of the CPB-SiPs was needed to fabricate a quasi-solid film. In addition, we investigated the ionic properties of the quasi-solid PS/DEME-TFSI-blended film. Owing to continuous ion channels composed only of DEME-TFSI, the film exhibited an ionic conductivity of 0.1 mS/cm, which is relatively high compared to previously reported quasi-solid electrolytes. Finally, we demonstrated that an electric double-layer capacitor fabricated using this film as the electrolyte exhibited high charge/discharge cycling stability and reversibility.
具有可控相分离结构的不混溶复合材料在从催化到电池等领域都很重要。我们通过添加由表面引发的原子转移自由基聚合制备的精确设计的浓聚合物刷接枝（CPB接枝）二氧化硅纳米颗粒（CPB-SiP），成功地控制了聚苯乙烯（PS）与两种离子液体（IL）（即N，N-二乙基-N-（2-甲氧基乙基）-N-甲基铵双（三氟甲基磺酰基）亚胺（DEME-TFSI）和1-乙基-3-甲基咪唑鎓双（三氟甲基磺酰基）亚胺）的不混溶共混物的相分离结构。我们讨论了CPB的化学种类和分子量与相分离结构之间的关系。当CPB由适当分子量的PS均聚物组成时，IL相形成连续结构，并且由于CPB-SiP吸附在PS/IL界面并防止宏观相分离，成功制备了准固态共混膜。我们提出，CPB-SiP的吸附和准固态膜的制备受基体PS链向CPB中的渗透程度和CPB-SiP的可变形性控制。我们发现，DEME-TFSI域尺寸可以通过CPB-SiP含量来控制，并且仅需要1 wt%的CPB-SiP即可制备准固态膜。此外，我们研究了准固态PS/DEME-TFSI共混膜的离子性质。由于仅由DEME-TFSI组成的连续离子通道，该膜表现出0.1 mS/cm的离子电导率，与先前报道的准固态电解质相比相对较高。最后，我们证明了使用该膜作为电解质制备的双电层电容器表现出高的充/放电循环稳定性和可逆性。
