The synchrotron-based hard X-ray nanotomography beamline, named 7C X-ray Nano Imaging (XNI), was recently established at Pohang Light Source II. This beamline was constructed primarily for full-field imaging of the inner structures of biological and material samples. The beamline normally provides 46 nm resolution for still images and 100 nm resolution for tomographic images, with a 40 µm field of view. Additionally, for large-scale application, it is capable of a 110 µm field of view with an intermediate resolution.

A completely new route was established to synthesize valuable primary amines from alkenes by using aqueous ammonia, that is, a simple photocatalytic hydroamination of alkenes using aqueous ammonia with a metal-loaded TiO2 photocatalyst. Although the photochemical hydroamination prefers to form amines according to Markovnikov rule, the new photocatalytic hydroamination gives anti-Markovnikov products predominantly. With an Au-loaded TiO2 photocatalyst, the amine yield reached up to 93% and the regioselectivity of anti-Markovnikov products was above 98%. The reaction mechanism was proposed for the new photocatalytic hydroamination. ASSOCIATED CONTENT Supporting Information.Additional data and NMR analysis. This material is available free of charge via the Internet at http://pubs.acs.org.

Ion gels composed of copolymers and ionic liquids (ILs) have attracted great interest as polymer gel electrolytes for various electrochemical applications. Here, we present highly robust ion gels based on a six-arm star-shaped block copolymer of (poly(methyl methacrylate)-b-polystyrene) 6 ((MS) 6 ) and an ionic liquid of 1-ethyl-3-methylimidazolium bis(trifluoromethyl sulfonyl)imide ([EMI][TFSI]). Compared to typical ion gels based on linear polystyrene-bpoly(methyl methacrylate)-b-polystyrene (SMS), the (MS) 6based gels show mechanical moduli of more than twice under various strains (e.g., stretching, compression, and shear). In addition, the outstanding mechanical property is maintained even up to 180 °C without a gel−sol transition. To demonstrate that (MS) 6 -based ion gels can serve as effective gel electrolytes for electrochemical applications, tris(2,2′bipyridyl)ruthenium(II) (Ru(bpy) 3 2+ ), a representative electrochemiluminescent (ECL) luminophore, is incorporated into the gels. In particular, flexible ECL devices based on (MS) 6 gels exhibit high durability against bending deformation compared to devices with gels based on linear SMS having a similar molecular weight and a composition. This result implies that star-shaped block copolymers are effective gelators for achieving flexible/wearable electrochemical electronics.

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.