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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.

A facile approach to block copolymer (BCP) domain orientation control in thin films has been demonstrated by employing a BCP with liquid crystalline semifluorinated side chains by tuning the composition of the copolymers of the bottom surface layer (BSL). 1H,1H,2H,2H-Perfluorodecanethiol was attached to a precursor polymer, polystyrene-block-poly(glycidyl methacrylate) (PS-b-PGMA), to obtain a novel BCP with a C8F17-containing liquid crystal (LC) side chain (PS-b-P8FMA). Anisotropic hexagonally packed cylinder domains in a bulk state were first characterized by transmission electron microscopy (TEM) and small angle X-ray scattering (SAXS). The observed morphology transition of BCPs with different fluorinated side chain lengths of –CF3, –C4F9, and –C6F13 suggested the decisive effects of LC side chain ordering on the anisotropic nanostructures. In the thin film study, poly(methyl methacrylate-random-2,2,2-trifluoroethyl methacrylate-random-methacrylic acid) (PMMA-ran-PTFEMA-ran-PMAA) solution was used as BSLs for tuning the desired periodicities. The surface free energy (SFE) of BSL was simply tailored by changing the composition of comonomers. In atomic force microscopy (AFM) characterization, long-range ordered perpendicularly oriented BCP domains in a hexagonally packed array or parallel oriented BCP domains as striation patterns were easily fabricated on non-preferential or preferential BSL, respectively. The study presents a novel approach to tunable thin film periodicities without changing or modifying BCPs, which is desired in next-generation BCP lithography.

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

Structural defects in graphene directly influence its electronic structure and can lead to the development of unique properties. However, the introduction of defects into ordered mesoporous graphitic carbons has yet to be demonstrated. Herein, defects were successfully introduced into the graphitic carbon lattice of well-ordered hexagonal mesoporous carbons via a block copolymer soft-template method and high-temperature carbonization. Small-angle X-ray scattering, scanning electron microscopy, and nitrogen adsorption measurements revealed that well-ordered ~4 nm cylindrical mesoporous structures with high surface areas (532 m2g−1) and good mesoporosity were maintained after high-temperature carbonization up to 1500 °C and mechanical milling. Raman and CHN elemental analyses suggested that defects were introduced into the graphitic carbon lattice through surface reconstruction induced by N-atom removal during heat treatment. The obtained robust and well-ordered N-containing mesoporous carbons with deliberately introduced defects are considered promising materials for electrochemical reactions and as catalyst supports. The introduction of structural defects into ordered mesoporous carbons is demonstrated based on block copolymer-templating and high-temperature carbonization of N-containing polymers. N-atom removal during high-temperature heat treatment induces structural defect formation, and the use of soft-templating yields dense mesostructures tough enough to maintain ordering upon defect introduction.Please change the graphical abstract to the revised one sent by email separately.

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, ...