Mesoporous metal oxides consisting of fully interconnected network structures with small pores (20–50 nm) have high surface areas and decreased ion intercalation distances, making them ideal for use in high-performance electrochromic supercapacitors (ECSs). Evaporation-induced self-assembly (EISA), which combines sol–gel chemistry and molecular self-assembly, is a powerful method for the fabrication of mesoporous metal oxides through a solution phase synthesis. Herein, we introduce ultrafast sub-1 s ECSs based on an amorphous mesoporous tungsten trioxide (WO3) that is prepared by EISA. Compared to that of a compact-WO3 film-based device, the performances of an ECS with mesoporous WO3 exhibits a large optical modulation (76% at 700 nm), ultrafast switching speeds (0.8 s for coloration and 0.4 s for bleaching), and a high areal capacitance (2.57 mF/cm2), even at a high current density (1.0 mA/cm2). In addition, the excellent device stability during the coloration/bleaching and charging/discharging cycles is observed under fast response conditions. Moreover, we fabricated a patterned mesoporous WO3 for ECS displays (ECSDs) via printing-assisted EISA (PEISA). The resulting ECSDs can be used as portable energy-storage devices, and their electrochromic reflective displays change color according to their stored energy level. The ECSDs in this work have enormous potential for use in next-generation smart windows for buildings and as portable energy storage displays.

We investigated, via small-angle X-ray scattering and transmission electron microscopy, the morphologies of binary blend of polyisoprene-b-polystyrene-b-poly­(2-vinylpyridine) (ISP) triblock terpolymer and polyisoprene-b-polystyrene (IS) diblock copolymer. An asymmetric ISP with volume fractions (f) of 0.12, 0.75, and 0.13 for PI, PS, and P2VP blocks, respectively, showed a new morphology: coexistence of spheres and cylinders with tetragonal packing. Asymmetric IS with f I = 0.11 and f S = 0.89 showed conventional body-centered cubic spherical microdomains. Very interestingly, a binary blend of ISP and IS with overall volume fractions of f I = 0.12, f S = 0.79, and f P = 0.09 exhibited core–shell double gyroid (CSG: Q230 space group), where PI consists of thin core and PS forms thick shell, while P2VP becomes thin matrix. It is very unusual to form CSG even at highly asymmetric volume fractions.

We synthesized polystyrene-[polystyrene-b-poly(2-vinylpyridine)] 3 miktoarm star copolymer [PS L -(PS S -b-P2VP) 3 ], where PS L and PS S are long and short PS chains, respectively, by the combination of anionic polymerization, atom transfer radical polymerization (ATRP), and click reaction. We changed the volume fraction of the PS block (f PS ) and the chain asymmetry of the PS chain τ = f PS,L /(f PS,L + f PS,S ). Phase behavior of PS-(PS-b-P2VP) 3 was investigated by transmission electron microscopy (TEM) and small-angle X-ray scattering (SAXS). Inverted gyroids consisting of PS chains were formed at f PS = 0.64 and τ = 0.65, while asymmetric lamellae were observed at f PS = 0.81 and τ = 0.79. Because a long PS chain (PS L ) and three short PS S -b-P2VP copolymer chains are linked at a single junction point, a huge configurational entropy penalty was expected, resulting in distorting the original phase boundaries observed for conventional AB diblock copolymer. PS S -b-P2VP chains are mainly located at the interface between PS and P2VP microdomains, whereas PS L chains fill the regions far from the interface, which causes a radial distribution to form interfacial curvature. Interestingly, the phase behavior was greatly affected by τ at a fixed f PS . For instance, at a fixed f PS (0.64), an inverted gyroid structure was formed at τ = 0.65, while a lamellar structure was observed at τ = 0.46. With the decrease in τ (or the difference of molecular weight between PS L and PS S becomes smaller), the interfacial curvature is not expected because all PS S -b-P2VP chains have no need to be arranged in the same direction. The experimental results are consistent with the predictions based on self-consistent field theory (SCFT).

We investigated the morphology formed in the binary blend of six-arm star-shaped (poly­(methyl methacrylate)-block-polystyrene)6 copolymer [(PMMA-b-PS)6] and PMMA-b-PS linear diblock copolymer by varying their molecular weights as well as volume fractions of the blocks. When the molecular weight of PMMA-b-PS is much larger (> ∼4) than that of one arm of (PMMA-b-PS)6, PMMA-cylindrical microdomains are formed even though the volume fraction of PMMA (f PMMA) in both (PMMA-b-PS)6 and PMMA-b-PS is nearly symmetric (f PMMA ∼0.5). On the other hand, when the ratio of molecular weights between these two copolymers is not large, lamellar morphology is observed in the blend as expected. Very interestingly, we found that even for a binary blend with the overall volume fraction of the PMMA block (f̅ PMMA) as large as 0.71, the major PMMA blocks still aggregate into cylindrical microdomains, and thus, “inverted cylinders” are formed, although PS-cylinders are observed in the neat (PMMA-b-PS)6 and PMMA-b-PS melts. This interesting inverted cylinder is mainly stabilized by two factors. On the one hand, the long linear diblock copolymer swells the domain significantly, thus preventing the short (PMMA-b-PS)6 star copolymer from forming the favorable bridging configurations in order to avoid the high stretching energy. As long as the bridging configurations are prohibited, the PMMA-core blocks of (PMMA-b-PS)6 prefer to stay inside the curvature, amplifying the tendency of forming a spontaneous curvature toward PMMA-blocks. On the other hand, the radial distribution of the long PMMA-block of the diblock and the short PMMA-block of the star increases the spontaneous curvature. The experimental results as well as the formation of the inverted cylinders have been verified by self-consistent field theory (SCFT).

We obtained the end-on orientation of poly­(3-dodecylthiophene) (P3DDT) chains where the main chains are vertically oriented on a substrate by synthesizing poly­(3-dodecyl­thiophene)-block-poly­(3-(2-(2-(2-methoxy­ethoxy)­ethoxy)­ethoxy)­methyl thiophene) copolymer (P3DDT-b-P3TEGT) with two different weight fractions of P3DDT block (w P3DDT = 0.48 and 0.65). Both block copolymers showed well-ordered lamellar microdomains in bulk, verified by small-angle X-ray scattering (SAXS). Because of the high incompatibility of the two blocks, P3DDT-b-P3TEGT thin films prepared by spin-coating on a substrate followed by thermally annealing showed parallel oriented lamellar microdomains to the substrate. Hydrophilic P3TEGT microdomains were located at the substrate/polymer interface, while hydrophobic P3DDT microdomains were located at the polymer/air interface. Thus, both P3DDT and P3TEGT backbone chains were oriented perpendicularly to the lamellar layer (namely, film thickness direction), and the end-on orientations of P3DDT and P3TEGT chains were obtained. The hole mobility was measured by fabricating a space-charge-limited current (SCLC) device. P3DDT-b-P3TEGT showed much enhanced mobility compared with the device made of neat P3DDT film with edge-on orientation, indicating that end-on orientation is very effective for improving the hole mobility along the vertical direction.