Original Article in 2011

Gold was vacuum deposited on one side of 6-μm-diameter silica-gel particles to prepare Janus particles (JPs). Thiol-terminated pH-responsive poly(sodium 6-acrylamidohexanoate) (pAaH-SH) was immobilized onto the gold surface of JPs. pH-responsive flocculation and dispersion behavior of pAaH-grafted JPs can be observed with optical and fluorescence microscopy measurements.

Superhydrophobic coatings (water contact angle >150°) were synthesized by simultaneous spraying of oppositely charged polyelectrolytes and nanoparticles with a home-made spraying system. Polymeric ionic liquid poly[(1-vinyl-3-ethyl imidazolium) bis(trifluoromethane sulphonyl) imide] was used as a fluorinated polyelectrolyte alternative to Nafion. For getting superhydrophobic thin films, fumed silica nanoparticles and clay nanorods were introduced into the polyelectrolyte multilayer films. The polymeric ionic liquid derivative showed synthetic advantages compared with the classic fluorinated polyelectrolytes.

Coarsening behavior—optical micrographs of poly(ɛ-caprolactone) (PCL)/ poly(styrene-co-acrylonitrile) (SAN) (70/30) blend prepared by precipitation into methanol, during static annealing at 200 °C: after 1 and 2 min, the regularly phase-separated structure was achieved; after 6 min, the structure coarsened to the particles of approximately 10 μm in size in a matrix and small domains of approximately 1--2 μm in size appeared in both the particles and the matrix regions; after 15 min, the particles grew to several tens of microns and the number of small domains increased; after 15 min, quenching to 25 °C and crystallization—the large dispersed particles can be assigned to a PCL-rich region.

A new soluble conjugated polymer, poly[{9-(4-methoxyphenyl)-9H-carbazole}(9,9-dioctylfluorene)(2,5-diphenyl-1,3,4-oxadiazole)](PCFO), was synthesized and was sucessfully used to fabricate a PCFO-based nonvolatile memory device. This device showed typical bistable electrical switching and nonvolatile write-once read-many-times memory performance, with a turn-on voltage of about −2.3 V and an ON/OFF state current ratio of ∼10⁵.

The diisocyanate structure has an important role in the phase separation behavior of hybrid materials. SAXS curves for both PUs show the typical broad band at q=0.1 Å⁻¹. Incorporation of the acrylic component reduced the intensity of this maximum. Hybrid based on H12MDI has a high degree of phase mixing for 50 wt% acrylic content but a separated phase at 70 wt% is observed. TMXDI-based hybrids that form homogeneous systems with higher acrylic content and phase separation are observed only at 90 wt%.

Conformation of poly(γ-benzyl-L-glutamate) (PBLG) in the block copolymers in which polystyrene (PS) was attached to the N terminus (PBLG_n-N-PS_m) or the C terminus (PS_n-C-PBLG_m) of PBLG was studied in trifluoroacetic acid (TFA)–chloroform mixture at various concentrations. Contribution of the PS segment to helix–coil transformation of PBLG was obvious in PS_n-C-PBLG_m rather than in PBLG_n-N-PS_m, indicating that conformational free energy of the C terminus in the PBLG chain differs from that of the N terminus.

A microfluidic device with three-dimensional flow channels is fabricated by stereolithography according to a computer-aided design (CAD) model. By injecting water and oil phases into the device, a monodisperse water-in-oil emulsion is formed. We show that monodisperse thermosensitive poly(-isopropylacrylamide) gel particles can be prepared by photopolymerization of a gelation reagent dissolved in the water phase.

Structure studies were performed on PVA gels in mixtures of dimethyl sulfoxide (DMSO) and water using various scattering methods to see the hierarchic structure. It was found that the crosslinking points are crystallites, the nearest-neighboring distance is 180–200 Å and the bicontinuous structure due to phase separation is in μm scale for the gel in DMSO/water (60/40). Dynamics of three kinds of PVA gels were also studied in nm scale using neutron spin echo technique.

Transmission electron microscopy micrograph of (70/30) poly(p-phenylene sulfide)/poly(ethylene-ran-methylacrylate–ran-glycidyl methacrylate) blend containing numerous micelles of copolymers formed in situ during melt mixing in the dispersed phase (stained by RuO₄).

We found that the inclusion complexes composed of amylose and poly(glycolic acid-co-ɛ-caprolactone) (P(GA-co-CL)) of a biodegradable polyester were prepared by phosphorylase-catalyzed polymerization of α-D-glucose 1-phosphate from maltoheptaose as a primer in the presence of P(GA-co-CL) (vine-twining polymerization). In addition, it was found that lipase-catalyzed hydrolysis of P(GA-co-CL) in the inclusion complex was partly inhibited.

A bio-based fibrous film aimed to be used as food-packaging component was electrospun from blend solutions of cellulose acetate (CA) and poly(ethylene oxide) (PEO). CA/PEO blend ratios were varied to unveil the effect of PEO on morphology, moisture-adsorption and tensile properties of the blend fibrous films. The results indicated that the addition of PEO could improve tensile strength, elongation and elasticity of the CA-based fibrous film. Zinc oxide nanoparticles incorporated into the blend fibers were shown to improve tensile and thermal properties of the nanocomposite film.

Rod-like capsules consisting of a thin crosslinked poly(vinyl acetate) (PVAc) shell and a calcium carbonate core were synthesized by suspension polymerization technique. The shell thickness ranged from 12 to 19 nm. The glass transition temperature T_g of the filled shell was revealed to be raised, whereas the dynamic length scale ξ(T_g) to be lowered from the bulk values. The T_g shift may be partly attributed to unstable configuration that is retained by the crosslink.

The coagulation size of freezable water in a poly(vinyl alcohol) (PVA) hydrogel was investigated as a function of the freeze/thaw cycle period using thermal analysis. For longer cycle periods, the coagulation size was larger.

Our study explored microstructures at skin, sub-skin and core zones of injection-molded carbon black particles/polypropylene composite. Figure 3 in the paper showed the schematic map on definition of each zone. We found that strong oriented microstructure was formed at core instead of at sub-skin, especially under lower packing pressure. A band with non-continuous conductive path was found under the action of higher injection process, and it will expand with lowering packing pressure.

The concept of controlling supramacromolecular self-assembly and disassembly of two building blocks (of polymers) with end-functional groups is displayed. By self-assembling two building blocks that carry non-covalent bonding moieties, a block copolymer-type supramacromolecule is formed via non-covalent bonding, resulting in a nanophase-separated structure with the length scale of the building blocks. By contrast, macrophase separation with a much larger length scale than the building blocks themselves can be observed if the two blocks are pulled apart under external stimuli such as heat or applied stress.

Polyrotaxane networks were synthesized by exploiting a Pd-templated bis-macrocycle as a topological cross-linker during radical polymerization. Radical polymerization of 4-vinylpyridine with the topological cross-linker in the presence of a catalytic amount of AIBN gave the network polymer as a gel. The addition of 4-tert-butylstyrene as a vinyl co-monomer to the polymerization system afforded a sufficiently stable gel as the polyrotaxane network, enabling the introduction of stopper moieties into the trunk polymer.

Bio-based thermosetting resins, biseugenyl succinate (BEUS) and bis(4-maleimidephenyl) succinate (BMIS) were synthesized from succinic acid and eugenol. The BEUS/BMIS cured at 230 °C for 1 h showed a higher glass transition temperature and a greater tensile strength than 2,2′-diallyl bisphenol A (DABA)/4,4′-bismaleimidediphenylmethane (BMIM) cured under the same condition. The Fourier Transform Infrared (FTIR) analysis of the cured materials revealed that chain polymerization of allyl and maleimide groups occurred to produce BEUS/BMIS, whereas a stepwise ene reaction and subsequent chain polymerization in addition to an etherification reaction occurred to produce DABA/BMIM.

This paper discusses an effective route in the graft copolymerization of methyl methacrylate monomer onto syndiotactic polystyrene (sPS) using free-radical polymerization, and the effect of an organophilic montmorillonite (O-MMT) on the final properties of the graft copolymer sample. The structure of vinyl-terminated sPS multicenter macromonomer and the graft copolymer were characterized by means of Fourier transform infrared and ¹H nuclear magnetic resonance spectroscopy. The exfoliated sPS-graft-poly(methyl methacrylate)/MMT nanocomposite was characterized by means of X-ray diffraction, transmission electron microscopy, thermogravimetric analysis and differential scanning calorimetry.

Photo-stimulated luminescence spectra (PSLS) emission from alumina-filled epoxy nanocomposites consisting of varying volume fractions of alumina nanoparticles was collected and analyzed to characterize dispersion within the sample through intensity maps. The measurements are based on integrated intensity data from the R1 curve of α-alumina throughout each specimen. This novel method has potential as a quality control method to determine the location of voids, inclusions and/or agglomerations, while in addition predicting the volume percentage of particles within a specimen.

Two different strategies have been successfully used to modulate the swelling capacity of thermo-responsive hydrogels based on 2-(2-methoxyethoxy)ethyl methacrylate: (1) controlling the crosslinking degree from varying the crosslinker type and amount, and (2) using N-isopropylacrylamide as comonomer, which in addition allows to modulate the volume and glass transition temperatures.