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To control the self-assembled morphology of block copolymers (BCPs), a series of BCPs were synthesized and post-functionalized via click chemistry. More specifically, polystyrene-b-poly(allyl glycidyl ether)s (PS-b-PAGEs) were synthesized via the anionic polymerization of styrene and subsequent catalyzed ring-opening polymerization of the second PAGE block. Thiol窶兎ne click chemistry was utilized for the post-functionalization of the resulting polymers. To investigate the effects of functional side-chains on the interaction between segments, the Flory窶滴uggins interaction parameter ﾏ� was estimated using the radon phase approximation method. The significant increases and decreases in the effective ﾏ� (ﾏ㌃ff) values obtained suggested that the introduction of functional groups significantly influenced ﾏ㌃ff. Moreover, the morphologies of the synthesized BCPs were then investigated using X-ray scattering and transmission electron microscopy, and it was found that the morphology was also affected by the introduction of functional groups.

Using a tailorable poly(styrene-block-glycidyl methacrylate-block-methyl methacrylate) (PS-b-PGMA-b-PMMA) triblock terpolymer, the effect of changing the Flory窶滴uggins interaction parameters (ﾏ�) on the bulk self-assembly behavior of 12 linear ABC triblock terpolymers was investigated. By introducing different thiols to the short, reactive PGMA middle block, the experimental ﾏ②B and ﾏ③C could be arbitrarily altered, thereby changing the self-assembled morphologies that were characterized by small-angle X-ray scattering and transmission electron microscopy. Observed morphologies included lamellae, hexagonal cylinders, and tetragonal cylinders, which were found to be in close agreement with the expected morphologies obtained by self-consistent field theory simulation. Extending the 12 experimental results, 400 simulations were carried out to construct the ﾏ②B窶苫③C phase diagrams of the terpolymer at four different degrees of polymerization. The experimental and simulation results demonstrated that both the magnitude and the relation among each of the three interaction parameters are vital in determining the self-assembled morphology.

Further development of next-generation block copolymer (BCP) lithography processes is contingent on comprehensive studies of the ordering dynamics of high-ﾏ� BCPs that can form sub-10 nm features on thin films. However, quantitative analyses of the degree of ordering on the surface and cross sections of thin films have been difficult to execute. To tackle this challenge, we employ a perpendicular lamella-forming high-ﾏ� BCP, poly(polyhedral oligomeric silsesquixone-block-2,2,2-trifluoroethyl methacrylate) (PMAPOSS-b-PTFEMA), and reveal that the high-ﾏ� PMAPOSS-b-PTFEMA requires three times the activation energy (Ea) compared to that of poly(styrene-block-methyl methacrylate) (PS-b-PMMA) for defect annihilation, at Ea = 2600 ﾂｱ 420 kJ mol窶�1, and a transition from a fast ordering regime with a growth exponent of ﾎｦ = 0.30 at lower orientational order parameters (ﾏ�2 < 0.36) to a slow ordering regime with ﾎｦ < 0.05 at ﾏ�2 > 0.36, where well-aligned lamellae restrict defect annihilations to enthalpically unfavorable glide mechanisms that require BCP intermixing.

A well-ordered mesoporous polyimide film was fabricated by a soft-template method using a microphase-separated structure of an amphiphilic block copolymer (BCP) as a template. Poly(amic acid)s (PAAs) as polyimide precursors and resol as a cross-linker for the stabilization of the nanostructure were found to be selectively miscible with the hydrophilic domain of the template BCP. Their mixture coassembled and formed the desired ordered nanostructures. The composite films tended to form well-ordered nanostructures when PAAs with a flexible domain such as ether or methylene were used. Mesoporous polyimide films were obtained on thermal treatment of the composite films formed via the sequential processes of cross-linking of the resol, imidization of the PAAs, and selective decomposition of the template BCPs. A polyimide film with well-ordered hexagonal-packed cylindrical mesopores was successfully fabricated after the thermal treatment of the composite film based on PAA/polystyrene-block-poly(methacrylic acid)/resol. The domain spacing based on small-angle X-ray scattering was 29.4 nm, and the pore diameter was determined by scanning electron microscopy to be 竏ｼ19 nm.

A new class of periodically nanostructured polythiophene materials with high regularity and numerous morphologies is prepared through the cooperative self-assembly of polythiophene derivatives with a templating block copolymer (BCP) and poly(1,4-isoprene)-block-poly(methacrylic acid) (PMA). The selection of the hydrophilic and aprotic triethylene glycol (TEG) group as side chains on polythiophene and the use of hydrophilic and protic PMA are crucial to producing well-ordered nanostructures in polythiophene films, as it enables selective coassembly within the hydrophilic domain through hydrogen bonding. The composite films are shown to have formed hexagonally packed cylinders with 28?nm periodicities based on small-angle X-ray scattering and transmission electron microscopy. The formation of hydrogen bonding is revealed by a shift in the carbonyl peak of PMA in the Fourier transform infrared spectra of the composite film relative to the neat film. This suggests that the TEG-functionalized polythiophene selectively incorporates into PMA. ? 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019, 57, 1105?1112

A hyperbranched aromatic poly(ether ketone) functionalized with 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO/HBPEK) was investigated as a novel heterogeneous catalyst for aerobic oxidation of alcohols. The TEMPO/HBPEK contained 2 mmol g-1 TEMPO and had a turnover number (TON) of 46 compared to commercial TEMPO with a TON of 60, indicating good catalytic activity and selectivity for the aerobic oxidation of benzyl alcohol. This material can be used as a recyclable heterogeneous catalyst by grafting it onto insoluble supports such as carbon black (TEMPO/HBPEK/CB) or polyimide nanoparticles (TEMPO/HBPEK/PI), whereas the bare TEMPO/HBPEK acts as a homogeneous catalyst. These heterogeneous catalysts had TONs of 27 and 22, respectively, indicating greater catalytic activity than the commercially available heterogeneous catalyst, TEMPO immobilized on polystyrene, which had a TON less than 1.

A versatile, solvent free aerobic alcohol oxidation system has been established in the presence of benzaldehyde based on a heterogenous cobalt catalyst supported on nanoshell carbon (Co/NSC), which was prepared through the pyrolysis of a mixture of Co(II) phthalocyanine and phenol resin. The established system features equal efficiency toward both benzylic alcohols and aliphatic alcohols. The nanoshell carbon has been demonstrated to be a better supporting material for the present reaction than some other carbon materials, e.g., activated carbon. Mechanistic studies suggest that Co/NSC can catalyze the formation of oxidative intermediate peroxybenzoic acid as efficiently as homogeneous cobalt catalyst, and moreover, suppress the undesired Baeyer–Villiger side reaction. Co/NSC also exhibits good reusability, i.e., it can be reused for at least 10 times without significant loss of performance.

The incorporation of nitroxide radicals into a nitric acid-assisted carbon-catalyzed oxidation system (NACOS) afforded a highly efficient, widely applicable, non-metallic approach for the selective aerobic oxidations of alcohols. Without any solvent, this novel protocol has the ability to oxidize various primary alcohols to their corresponding aldehydes with selectvities as high as 99% at full conversions, with only 0.1 mol% of nitroxide radicals and < 4.5 wt% of activated carbon under mild conditions (temperatures as low as 50 °C and atmospheric pressure). The performances of several stable nitroxide radicals have been compared. The effects of nitric acid concentration, activated carbon loading, and temperature have been studied for the oxidation of benzyl alcohol. The enhanced NACOS represents a greener and more efficient fundamental chemical process, due to its use of molecular oxygen as an oxidant, and its solvent-free nature.

Preparation of low dielectric constant polyimides containing double-decker-shaped silsesquioxane (DDSQ) in the main chain with high molecular weights (ηinh = 0.61 dL/g) is reported. Double-decker-shaped silsesquioxane aromatic tetracarboxylic dianhydride (DDSQDA) was prepared by reaction of DDSQ aromatic diamine and pyromellitic dianhydride through functional group conversion method. The polyimides were synthesized from DDSQDA and several aromatic diamines by a one-step high temperature solution method. Introduction of DDSQ unit in polyimides endowed properties such as solubility in organic solvents, 10% weight loss temperatures (Td10) up to 570 °C in nitrogen, the glass transition temperatures (Tg) higher than 300 °C, good mechanical properties (tensile strengths of 72.3–82.1 MPa, initial modulus of 1.8–2.6 GPa, and elongation at breakage of 8.0–15.9%), transmittances over 80% at 400 nm, and a dielectric constant of 2.43 at 1 MHz. The polyimides were soluble in organic solvents such as DMAc, chloroform, ...