Articles in 2016

Epigenetics control carrier (EpC carrier) has been designed as a unique tool to control histone acetylation by simultaneous transfection of histone acetyltransferase gene and delivery of a histone deacetylase inhibitor.

Nanostructured composite electrolyte films consisting of a cross-linked lyotropic liquid crystal monomer and varying amounts of an organic carbonate liquid electrolyte and a Li salt were systematically prepared and characterized for their ionic conductivity and ability to function as the separator membrane in a Li-metal/fluorinated carbon test cell. Films with a well-defined bicontinuous cubic phase were sufficiently strong to act as an ion-conductive separator and displayed stable open-circuit potentials, whereas the majority of the mixed-phase films gave shorted cells.

This review article describes the current state-of-the-art research on organic photorefractive polymer composites. A historical background on photorefractive materials is first introduced and is followed by a discussion on the opto-physical aspects and the mechanism of photorefractivity. The molecular design of photorefractive polymers and organic compounds is discussed, followed by a discussion on optical applications of the photorefractive polymers.

Thermal reaction mechanism of γ-irradiated polytetrafluoroethylene (PTFE) is elucidated at the molecular level by kinetic analysis, where a new multichannel Fourier-transform chemiluminescence spectrometer was used.

A polymer cross-linking system undergoes a phase transition from liquid to solid at a critical point, which is called the sol-gel transition. We independently tuned the intrinsic parameters governing the sol-gel transition, that is, the connectivity and polymer concentration, using a model gel system (tetra-polyethylene glycol gel), and examined the model predictions. The lattice-based percolation model can be applied only for systems prepared around the overlapping concentration. In the case far below the overlapping concentration, the aggregation model well reproduced the transition behavior.

We report a controlled chain-growth polymerization of methyl 3-octylaminobenzoate having a bithiophene chromophore at the 5-position of the benzene ring with the improved polymerization activity, which gives poly(N-octyl-m-benzamide)s with the better solubility. The introduction of a terthiophene chromophore at the propagating end is also described. From spectroscopic data and theoretical investigations, it was found that neighboring bithiophene chromophores have the π–π interaction and the excited energy can migrate along the polymer chain.

Three approaches for directly reacting chemical agents and polymer chains with multi-walled CNTs (MWCNTs) are presented, including (i) sequential atom transfer radical addition/polymerization to MWCNTs; (ii) ozone-mediated addition reaction to MWCNTs; and (iii) Diels–Alder reaction-mediated MWCNT functionalization. On the basis of the reaction routes, the scopes and functions of MWCNT-based nanohybrids and nanocomposites have been extended.

The molecular weight of spider proteins contained in the major ampullate glands of spiders collected during different periods. The standard deviation is also indicated. A peak for molecular weight is observed in mid-autumn, which corresponds to the mating season.

We synthesized a series of poly(N-isopropylacrylamide)-based ionic hydrogels with dicationic ionic liquid crosslinking structures. The obtained ionic hydrogels showed typical feature of poly(ionic liquid) in aqueous solutions, of which the quaternized imidazolium moieties could interfacially interact with anionic dyes, such as methyl orange (MO), methyl blue (MB), congo red (CR), orange G (OG), thymol blue (TB) and bromothymol blue (BTB), which were strongly dependent on the chemical structures of the dyes.

A unique methodology to control the morphology and ion transport properties of block copolymer electrolytes by the inclusion of functional terminal groups.

A mixture of the micellar dispersions of linear PLLA–PEO–PLLA and linear PDLA–PEO–PDLA block copolymers formed a gel upon heating, whereas a mixture of the cyclic counterparts did not undergo this phase transition. These results suggest that the gelation behavior is directed by the topology of the polymer components. Furthermore, cyclic PLLA–PEO and cyclic PDLA–PEO block copolymers incorporating photocleavable o-nitrobenzyl units were synthesized. A mixture of the micellar dispersions of these block copolymers formed a gel upon ultraviolet (UV) irradiation via the ‘topological conversion’.

Pore formation on the liposome resulted from the photo-cross-linking reaction between DC_8,9PCs, which is a photo-polymerizable lipid, is only observed when the saturated lipids comprise of the hosting matrix. To understand the influence of the hosting matrix, the Langmuir monolayer is employed because the system is capable of precisely controlling the packing state and the compositions of the film. The kinetics of reaction is found to strongly depend on the packing state of the film, and the cross-distance between DC_8,9PCs plays a key role for the polymerization reaction to proceed.

The chemosensor-filter based on novel multifunctional fluorescent electrospun (ES) nanofibers exhibiting high sensitivity for various metal ions were prepared from binary blends poly(HEMA-co-NMA) and bpy-F-bpy by using a single-capillary spinneret. It shows apparent color change from blue (blank) to green, to blue-green and to be fluorescence quenching when detecting Zn²⁺, Hg²⁺ and Cu²⁺, respectively, and high reversibility. A microfluidics system study indicated that these nanofibers can be used as ‘naked eye’ sensors for sensing various metal ions and as efficient multifunctional chemosensor-filtering devices.

Three-arm and 6-arm poly(methyl acrylate)s (PMAs) were synthesized via atom transfer radical polymerization (ATRP) with 1,3,5-tris(bromomethyl)-2,4,6-trimethylbenzene and hexakis(bromomethyl)benzene as the initiators, CuBr as the catalyst and tris [2-(dimethylamino) ethyl] amine (Me₆TREN) as the ligand. The effect of the molar ratio of CuBr and Me₆TREN to Br of the initiator on the arm number was investigated. Hydrolysis of the products was conducted to convert the PMAs to poly(acrylic acid)s (PAAs). The solubility to water and thermal decomposition curves of 3-arm and 6-arm PAAs corresponded well to those of PAA.

Distribution of end of polymer in the filler-filled material is simulated using self-consistent field method. In our simulation results, the segregation of ends of polymer can be found at the interface of filler, though the depletion region of ends is also existed around the region in the distance of Rg from filler. Sizes and shape of filler are affected to the segregation of ends of polymer, and in the cases of smaller or spherical fillers, the density of ends of polymer near the interface of filler increases. These results can be explained by the entropic effect of polymer chain ends. The segregation of ends contributes to the stabilization of interface of filler adding the entropic part of free energy.

Drug loading and release abilities of freestanding films made of polyion complexes of chondroitin sulfate C and chitosan were examined using dye molecules such as methylene blue and carboxyfluorescein. The dye-loading films were prepared using pre- and post-loading methods. Microscopic film morphologies were not affected by the dye loadings. The mechanical strengths of the dye-loaded films were almost identical to those of the unloaded films. The dye release behaviors of the films in various aqueous solutions were examined, and the results demonstrated that the films exhibited media-responsive dye release abilities.

Silicon- and carbon-bridged polythiophenes, dithienosilole (DTS) and cyclopentadithiophene (DTC) homopolymers with 2-ethylhexyl or n-octyl substituents on the bridging atom, were synthesized and their optical and electrochemical properties were investigated. OFET devices containing the present polymer films as the active layers were fabricated to investigate their carrier transport properties. The device based on a DTS polymer with n-octyl substituents showed much higher carrier mobility than that of the DTC polymer with the same substituents.

Artificial sheet-like nanocelluloses composed of cellulose oligomers with the cellulose II allomorph were synthesized by phosphorylase-catalyzed enzymatic reactions, and their hydrolytic activities against ester substrates were characterized. The as-prepared nanocelluloses exhibited relatively low hydrolytic activities. However, distorted and smaller nanocelluloses with larger surface areas, which were prepared by sonication-based mechanical treatment of the as-prepared nanocelluloses, exhibited significantly greater hydrolytic activities.

Nature-inspired material design concepts and recent progress on anti-fouling polymer materials are reviewed, and our recent researches on anti-fouling studies with polymer brushes are summarized. Zwitterionic polyelectrolyte brush immobilized surfaces represent significant anti-fouling for bio-macromolecules, oil foulants, marine fouling organisms and pipeline foulants. The anti-fouling mechanism was considered on the basis of the wetting, lubrication, hydrated chain dimension and hydrogen-bonding structure of hydrated water in the polyelectrolyte brushes.

The wrapping abilities of comb-like polymers with pendant conjugated fluorine moieties and their tunable electrical properties of SWNTs were discussed. It is found that longer side-chain-conjugated fluorene segments in homopolymer (P(St-Fl)₃₀₀, 7) can strongly bind to the SWNTs surfaces through π–π interaction and its copolymer (P2VP₇₉-co-P(St-Fl)₃₄₇, 5a) lead to predominant dispersion of SWNTs due to the flexibility of P2VP for further increasing the solubility. Thus, SWNTs wrapped by 5a after thermal annealing can be selected as a gate electrode, whereas the spin-coated SWNTs wrapped by 7 can be as a semiconductor for the FET channel, resulting in a mobility of 0.82 cm² V⁻¹s⁻¹, a threshold voltage of 0.35 V and an ON/OFF ratio of 2.8 × 10⁴.