Ion gels, composed of macromolecular networks filled by ionic liquids (ILs), are promising candidate soft solid electrolytes for use in wearable/flexible electronic devices. In this context, the introduction of a self-healing function would significantly improve the long-term durability of ion gels subject to mechanical loading. Nevertheless, compared to hydrogels and organogels, the self-healing of ion gels has barely investigated been because of there being insufficient understanding of the interactions between polymers and ILs. Herein, a new class of supramolecular micellar ion gel composed of a diblock copolymer and a hydrophobic IL, which exhibits self-healing at room temperature, is presented. The diblock copolymer has an IL-phobic block and a hydrogen-bonding block with hydrogen-bond-accepting and donating units. By combining the IL and the diblock copolymer, micellar ion gels are prepared in which the IL phobic blocks form a jammed micelle core, whereas coronal chains interact with each other via multiple hydrogen bonds. These hydrogen bonds between the coronal chains in the IL endow the ion gel with a high level of mechanical strength as well as rapid self-healing at room temperature without the need for any external stimuli such as light or elevated temperatures.

BaTiO3 and anatase with platelike particle morphology were prepared by using a hydrothermal soft chemical process. A layered titanate of K0.8Ti1.73Li0.27O4 with a lepidocrocite-like layered structure, which has a platelike particle morphology, was used as a precursor. In the first step, the layered titanate was treated with an acid solution to obtain an H+-form layered titanate H1.07Ti1.73O4·nH2O with a lepidocrocite-like layered structure. In the second step, the H+-form layered titanate was treated in a Ba(OH)2 solution or distilled water under mild hydrothermal conditions to transform the layered titanate to BaTiO3 or anatase. The transformation reactions were investigated by XRD and SEM analyses. There are two simultaneous mechanisms in the formation of BaTiO3 under the hydrothermal conditions. One is an in situ topotactic transformation reaction in the crystal bulk of the layered titanate, and another is a dissolution−deposition reaction on the surface of the particles. In the formation of BaTiO3, the in situ topotactic transformation reaction is predominant in the solution of low Ba(OH)2 concentration, while, in the formation of anatase, most of the reaction progressed by the in situ topotactic transformation mechanism. The platelike particles of BaTiO3 and anatase, which were prepared by this method, showed a high degree of crystal-axis orientation.

Barium titanate (BaTiO3) particles with book‐like and spherical morphology were prepared by using a hydrothermal soft chemical process in the presence of a cationic surfactant. A layered titanate of H1.07Ti1.73O4 with a lepidocrocite‐like structure and plate‐like particle morphology was used as the precursor. The layered titanate was hydrothermally treated in a Ba(OH)2–(HTMA‐OH) (n‐hexadecyltrimethylammonium hydroxide) solution or a Ba(OH)2–(HTMA‐Br) (n‐hexadecyltrimethylammonium bromide) solution in a temperature range of 80°–250°C to prepare BaTiO3. The intercalation reaction of HTMA+ with the layered titanate promotes the structural transformation reaction from the layered titanates to BaTiO3, while it inhibits the structural transformation reaction to anatase under the hydrothermal conditions. The particle morphology of BaTiO3 prepared by this method dramatically changes with changing reaction conditions. HTMA+ plays an important role in changing particle morphology in the hydrothermal soft chemical process.

The microstructures of ion gels formed by the self-assembly of an amphiphilic ABA-type triblock copolymer in an ionic liquid (IL) were explored by using atomic force microscopy (AFM) along with small-angle X-ray scattering (SAXS) to correlate it with the ion transport and mechanical properties. Polystyrene-b-poly­(methyl methacrylate)-b-polystyrene (PSt-b-PMMA-b-PSt) triblock copolymers with different PSt volume fractions were synthesized, and their self-assembled ion gels in 1-ethyl-3-methylimidazolium bis­(trifluoromethanesulfonyl)­amide ([C2mim]­[NTf2]) were prepared with various IL contents. From the AFM images, disordered micelle (DM), hexagonally packed cylinder (HEX), and lamellar (LAM) microstructures composed of hard phase-separated PSt blocks and soft PMMA block swollen by the IL were clearly observed, and the structures were consistent with the SAXS results. In cylinder and lamellar structures, polydomain structures were predominant, in which directionality and regularity are maintained in a small domain (approximately several hundred nanometers), although the domains were randomly packed on a larger scale. With respect to the mechanical properties, reversed HEX and LAM structures (where hard PSt can form a continuous phase) exhibited significantly higher storage moduli below the glass transition temperature (T g) of PSt than those above T g of PSt. Conversely, the effect of T g for DM and HEX microstructures was relatively low and can be ascribed to the absence of the continuous phase of PSt. The ionic conductivity measurements indicated that DM microstructures exhibited a small tortuosity (τ ≈ 1), that is, less obstacles in the diffusion path formed by the soft domain (PMMA with dissolved IL). Meanwhile, HEX and LAM microstructures exhibited significantly higher τ values although they display a continuous phase of the soft domain, which was ascribed to the polydomain structures formed in the ion gel. The results demonstrated a significant effect of microstructures as well as the important effect of polydomain structures on the transport and mechanical properties of ion gels.