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Volume 56, Issue 12
Displaying 1-17 of 17 articles from this issue
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Qui TRAN-CONG-MIYATA, Katsunari KATAOKA, Kouichi ENDOH1999 Volume 56 Issue 12 Pages 753-761
Published: December 25, 1999
Released on J-STAGE: March 15, 2010
JOURNAL FREE ACCESSAnisotropic phase separation of polystyrene/poly (vinyl methyl ether) (PS/PVME) blends was induced by taking advantages of polarization-selective reactions. Two types of photochemical reactions were used: photodimerization of anthracene and photoisomerization of stilbene. Anthracene and stilbene were separately chemically labeled to polystyrene which was mixed with PVME at various compositions to obtain samples for experiments. It was found that the anisotropic phase separation of these blends is significant when the experimental temperatures are below the glass transition temperature of the labeled polystyrenes. From the time-evolution of these anisotropic morphologies, the phase separation kinetics was discussed in conjunction with the reaction kinetics under irradiation with linearly polarized light. The evidence for the interference of unstable modes growing with different rates along different orientations in the irradiated blend, was experimentally found for both cases. These results suggest that the couplings between anisotropic reactions and fluctuations are responsible for the emergence of the anisotropic morphology.View full abstractDownload PDF (4479K) -
Takashi HONDA, Shinji URASHITA, Hiroshi MORITA, Ryuichi HASEGAWA, Tosh ...1999 Volume 56 Issue 12 Pages 762-771
Published: December 25, 1999
Released on J-STAGE: March 15, 2010
JOURNAL FREE ACCESSThe dynamic mean field theory is applied to various problems on polymer dynamics. (1) Domain structures in various phase separating polymer systems such as (a) A, B polymer blends, (b) A, B polymer blends with A-B block copolymers, and (c) A-B block copolymers with comb-structure are calculated. (2) Realistic simulations for a PE/PP/PS polymer blend are performed, where the segment interaction parameters determined by the method of the additive group contributions are used. The core shell structures observed experimentally are reproduced. (3) Polymer films consisting of insoluble polymers on solid wall are simulated. (4) Behavior of polydisperse polymers near a hard wall is studied. (5) Micellization of diblock copolymers and grafted polymers in solvent is simulated using a new method combining the mean field theory and the Rouse dynamics. Finally, further extension of the dynamic mean field calculations is discussed.View full abstractDownload PDF (12476K) -
Yuichi YAMASAKI, Kenichi YOSHIKAWA1999 Volume 56 Issue 12 Pages 772-785
Published: December 25, 1999
Released on J-STAGE: March 15, 2010
JOURNAL FREE ACCESSRecent progress in our understanding on collapse transition in single giant deoxyribonucleic acid (DNA) chains, i. e., a coil-globule transition, is reviewed. The collapse transition of DNA is induced with various kinds of condensing agents; multivalent cations, neutral polymers with salts, and alcohol. The development of fluorescence video-microscopy allows the direct observation on the collapse transition in a single DNA. The dependence of the transition point on the valence of multivalent cations observed by the experimental results, can be well explained theoretically with the inclusion of the effect of translational entropy of the counterions. A theoretical simulation indicates the existence of various different collapsed products from the single polymer chain. In the collapsing transition of DNAs, relatively wide regions are noted for the coexistence between elongated and collapsed states. The coexistence is classified with the two different types; interchain phase-separation and intrachain phase-separation. The observation with electron microscopy and AFM have demonstrated the actual existence of the intrachain phase-segregation, i. e., the partial globular structure. It is stressed that the collapsed products of DNA lose almost all of the negative charge.View full abstractDownload PDF (8682K) -
Masahiro FUJITA, Kyo Jin IHN, Masaki TSUJI, Shinzo KOHJIYA1999 Volume 56 Issue 12 Pages 786-796
Published: December 25, 1999
Released on J-STAGE: March 15, 2010
JOURNAL FREE ACCESSPolyethylene (PE), polyoxymethylene (POM), and poly (3-oxotrimethylene) (POK) were epitaxially crystallized from respective solutions onto the (001) face of alkali halides, and the morphologies of resultant crystals were studied by transmission electron microscopy (TEM). Rodlike crystals of each polymer were oriented in some crystallographic directions of the substrate surface. Bright-field and dark-field observations and selected-area electron diffraction experiments revealed that the rodlike crystals are edge-on lamellae. The thickness of the crystalline core in the edge-on lamella was found to be about 60% of the corresponding lamellar thickness. It was concluded that each of the folded-chain single crystals of the polymers under consideration consists of a crystalline core and a certain but somewhat less-ordered surface layer, containing folds, on each side of the core. This structure model could be visualized, at molecular level resolution, by high-resolution TEM of the POK edge-on lamellae.View full abstractDownload PDF (12463K) -
X.M. DAI, H. GOTO, K. AKAGI, H. SHIRAKAWA1999 Volume 56 Issue 12 Pages 797-806
Published: December 25, 1999
Released on J-STAGE: March 15, 2010
JOURNAL FREE ACCESSNovel liquid crystalline (LC) polyacetylene derivatives were synthesized to develop advanced LC conducting polymers with an ability of quick response to an electric field used as an external force. In practice, we synthesized ferroelectric LC (FLC) conducting polymers by introducing fluorine-containing chiral LC groups into side chains of polyacetylenes. Phase transition behaviors of these polymers were examined by differential scanning calorimetry and polarizing optical microscopy. Mesophases as well as higher order structures were evaluated with X-ray diffraction (XRD) measurements. All of the polymers exhibited mesophases in the heating and cooling processes. Two of the polymers synthesized showed twist grain boundary A (TGB*A) and chiral smectic C (S*c) phases in the heating and cooling processes. The temperature range of the S*c phase was wider than 50°in the cooling process. The observation of the S*c phase allowed us to expect that the polymer would exhibit the ferroelectricity.View full abstractDownload PDF (10276K) -
Toru SHIMIZU, Hong Zhen LI, Tatsuya HAYANO, Takashi YAMAMOTO1999 Volume 56 Issue 12 Pages 807-813
Published: December 25, 1999
Released on J-STAGE: March 15, 2010
JOURNAL FREE ACCESSWe investigate the structure formation of the long chain molecules by molecular dynamics simulation. In this paper, we have special interest in the melting, crystallization, and membrane formation, all in the presence of a free surface. The crystal with free side surfaces is shown to have characteristic structural instability at higher temperatures, and to melt and recrystallize at a temperature considerably lower than the melting point. Furthermore, the crystallization from the melt is found to occur preferentially at the free surface, resulting in the formation of a well-developed three-dimensional crystal. Lastly, the surface membrane on the liquid is found to show dynamical stability; here the molecules frequently change their positions from the membranes to the underlying liquid, and vice versa.View full abstractDownload PDF (9181K) -
Chizuko FURUKAWA, Shinichi SAKURAI, Fumiyoshi IKKAI, Shunji NOMURA1999 Volume 56 Issue 12 Pages 814-820
Published: December 25, 1999
Released on J-STAGE: March 15, 2010
JOURNAL FREE ACCESSIt has been found that a peculiar concentric-ring pattern of surface undulation is macroscopically formed on a cast film of a lamellar-forming SBS (polystyrene-block-polybutadiene-block-polystyrene) triblock copolymer when cast from its toluene solution under a temperature gradient. In this study, we examined the influence of air stream on the pattern. It was found that sets of the concentric rings aligned approximately along the air stream. Further quantitative image analyses revealed that there appeared two correlation lengths in the distribution of centers of the concentric rings when the air stream was appropriately imposed, while the shorter correlation length only existed in the case of no (or weak) air stream. The shorter correlation length is almost identical to the distance between the nearest neighbor of the centers, whereas the longer one corresponds to the distance between two neighboring sets of centers which aligned approximately along the air stream. In order to discuss quantitatively the influence of the air stream on the alignment of centers, a two-dimensional orientation factor for a vector which connects two closely neighboring centers was evaluated with respect to the direction of the air stream. Its influence on the number average and the standard deviation of the magnitude of the vector is also discussed. It is concluded that the air stream can be another control factor, independent of a temperature gradient, for self-organization of the surface undulation of the cast film of the SBS triblock copolymer.View full abstractDownload PDF (4965K) -
Masato HASHIMOTO, Tadasu AMASAKI, Takashi ITOH1999 Volume 56 Issue 12 Pages 821-827
Published: December 25, 1999
Released on J-STAGE: March 15, 2010
JOURNAL FREE ACCESSAn axialite is one morphology observed in high temperatures on crystal growth from the melt of polymers. It is important to consider the internal structure and the mechanism of growth of the axialite in order to study the mechanism of growth of polymer spherulite, which is a morphology similar to axialite. Axialites of isotactic polystyrene were observed with Optical Microscopy, Scanning Electron Microscopy, and Atomic Force Microscopy. The shape of axialites of isotactic polystyrene is evaluated quantitatively by using a new method. There exists a morphological transition at 203°C. Our various microscopic observations show that an axialite has a stack of many very small flat-on crystallites. The crystallites are binding at a screw dislocation and they are slightly rotated around it. We propose a model where the orientation of crystallites in an axialite has a normal distribution around the original growing direction with the standard deviation, a, which indicates the degree of disorder. This can explain the morphological transition at a critical temperature.View full abstractDownload PDF (6887K) -
Syozo MURAKAMI, Shinzo KOHJIYA, Tetsuya UCHIDA, Kaoru SHIMAMURA1999 Volume 56 Issue 12 Pages 828-832
Published: December 25, 1999
Released on J-STAGE: March 15, 2010
JOURNAL FREE ACCESSStructure of the extruded-blown film of high density polyethylene was studied by X-ray diffraction, SEM, and SPM. Lamellar bundles were piled up along the extrusion direction and oriented perpendicular to the extrusion direction. Close observation by SPM revealed that one lamellar bundle which looked like a single lamella by SEM was actually composed of ca. 6 lamellae. We propose that formation of such lamellar bundles may be due to self-vibration by rubbing with a die during the extrusion of melt.View full abstractDownload PDF (5846K) -
Yasushi OKUMURA, Kohzo ITO, Reinosuke HAYAKAWA, Toshio NISHI1999 Volume 56 Issue 12 Pages 833-836
Published: December 25, 1999
Released on J-STAGE: March 15, 2010
JOURNAL FREE ACCESSA molecular nanotube is a new kind of organic tubular molecule synthesized from cyclodextrin molecules of cyclic form. This nanotube has a constant inside diameter smaller than that of a carbon nanotube, and is soluble in several kinds of solvents such as water. In this study, we have observed by scanning tunneling microscopy a new kind of supramolecules formed by the molecular nanotubes and starpolymers with three branches. We found that the molecular nanotube includes a linear polymer chain chemically fixed to highly oriented pyrolytic graphite. Furthermore, we show that a dendritic structure is formed by molecular nanotubes and starpolymers on the substrate.View full abstractDownload PDF (3845K) -
Structural Analysis Based on Curvature DistributionsHiroshi JINNAI, Yukihiro NISHIKAWA, Hirokazu HASEGAWA1999 Volume 56 Issue 12 Pages 837-844
Published: December 25, 1999
Released on J-STAGE: March 15, 2010
JOURNAL FREE ACCESSBicontinuous microdomain structures appearing in diblock copolymers with copolymer composition of ca. 34-38% are studied from the viewpoint of interface curvatures. Since interface minimization is a major driving force of the structure formation in such systems, infinite periodic minimal surfaces (IPMS) with a variety of symmetries (or space groups) are often used as models. However, characterization of a bicontinuous structure often involves a controversial decision about which type of IPMS to employ. This decision is difficult because only two-dimensional images of the structures can be usually obtained by conventional transmission electron microscopy (TEM) and many IPMS reproduce a similar image in projection. However, recent developement of three-dimensional imaging of nm scale structures by TEM enabled us to measure the local interface curvatures. In the present study, we demonstrate that the local curvature distribution is a sensitive measure to distinguish the type of IPMS and hence the space group of the bicontinuous structures.View full abstractDownload PDF (9436K) -
Tomokazu FUJII, Atsushi TAKAHARA, Tisato KAJIYAMA1999 Volume 56 Issue 12 Pages 845-849
Published: December 25, 1999
Released on J-STAGE: March 15, 2010
JOURNAL FREE ACCESSThe surface structure of high-density polyethylene (HDPE) single crystals prepared by the self-seeding method was investigated by atomic force microscopy (AFM) and lateral force microscopy (LFM). Characteristic lozenge-shaped lamellar crystals of ca. 5μm long and ca. 12nm thick were observed with AFM. The contrast of the lateral force between neighboring sectors of the HDPE single crystal surface could be detected when the scanning direction was different between neighboring sectors. The magnitude of the lateral force increased with an increase of the scanning angle, θ, with respect to the (110) plane. These results indicate that the surfaces of the HDPE single crystals with Mw= 23k, 32k, 93k, 120k, and 520k prepared by the self-seeding method was composed of regular sharp chain-folds. It has been reported that the folding structure of the HDPE single crystal surface with Mw=520k prepared sporadically by a conventional isothermal crystallization method was switchboard-like structure. These results apparently indicate that the folding structure of the HDPE single crystal surface depends on the crystallization process or method.View full abstractDownload PDF (4004K) -
Yuji SAKURAI, Nobuhiro SATO, Shinzaburo ITO, Masahide YAMAMOTO1999 Volume 56 Issue 12 Pages 850-854
Published: December 25, 1999
Released on J-STAGE: March 15, 2010
JOURNAL FREE ACCESSPhase separation of a mixed monolayer of poly (octadecyl methacrylate) (PODMA) and poly (isobutyl methacrylate) (PiBMA) was investigated by Brewster angle microscopy (BAM) and atomic force microscopy (AFM). At 20°C, solid-like PODMA forms network-like structures including liquid-like PiBMA domains due to the strong cohesive force between the long alkyl side chains of PODMA. After annealing at 40°C for 60 min, the morphology of the mixed monolayer was drastically changed by the fusion of PODMA, resulting in a completely phase separated structure.View full abstractDownload PDF (7140K) -
Tetsu YONEZAWA, Shin-ya ONOUE, Toyoki KUNITAKE1999 Volume 56 Issue 12 Pages 855-859
Published: December 25, 1999
Released on J-STAGE: March 15, 2010
JOURNAL FREE ACCESSA close-packed one-dimensional array of gold nanoparticles was prepared with DNA as a rigid anionic polymer template. Gold nanoparticles with dense positive charges were prepared by modifying with dialkylammonium-disulfide. These cationic gold nanoparticles were adsorbed effectively on anionic DNA molecules. Electron microscopy indicated that the particle array had a close-packed structure with a small inter-particle distance. The formation mechanism of the close packing is discussed.View full abstractDownload PDF (4755K) -
Takayuki KURODA, Keigo TORIKAI, Hideko T. OYAMA, Toshiaki OUGIZAWA, Ta ...1999 Volume 56 Issue 12 Pages 860-864
Published: December 25, 1999
Released on J-STAGE: March 15, 2010
JOURNAL FREE ACCESSThe interfacial structure of immiscible bilayer films of amorphous polyamide (aPA) /polysulfone (PSU) was investigated by ellipsometry, atomic force microscopy (AFM), and transmission electron microscopy (TEM). The interfacial thickness of the annealed aPA/non-functionalized PSU sample was smaller than the measurable limit of ellipsometry (ca. 2nm). However, by grafting a maleic anhydride group to the PSU chain, the thickness increased to the order of 40nm at 200°C. It was also found from AFM measurements that the interface was undulated, with the scale of the lateral roughness being ca. 40nm. Therefore, it is likely that, during the interfacial reaction between the amine-terminated aPA and the MAH-functionalized PSU, an undulated interface was formed. This is probably because in situ formed copolymers entropically destabilized the interface by adopting a tightly packed conformation at high copolymer concentrations, which resulted in an increase of the interfacial area. The interfacial thickness determined by ellipsometry seems to include the contribution of the amplitude of the undulation.View full abstractDownload PDF (1628K) -
Takuya MITSUOKA, Atsushi MURASE, Motoyasu SUGIURA1999 Volume 56 Issue 12 Pages 865-868
Published: December 25, 1999
Released on J-STAGE: March 15, 2010
JOURNAL FREE ACCESS“Derivatization-electron probe X-ray microanalysis (EPMA) ” has been developed in order to analyze the distribution of 0.1% order functional groups in polymers with a gm level lateral resolution. A functional group in polymer is derivatized with a reagent containing a labeling element and then the distribution of the element corresponding to the original functional group is analyzed with EPMA. C=C in a powder slush molding poly (vinyl chloride) film and OH in a recycled polypropylene film were analyzed by Derivatization-EPMA. As a result, μm level distribution of the functional groups was revealed visually and it was confirmed that Derivatization-EPMA is useful for studies on polymer degradations and evaluations of polymer blends.View full abstractDownload PDF (3701K) -
Hirotsugu YOSHIDA, Kenji YAMAUCHI, Toshimitsu MATSUI1999 Volume 56 Issue 12 Pages 869-872
Published: December 25, 1999
Released on J-STAGE: March 15, 2010
JOURNAL FREE ACCESSThe morphologies of weld interfaces between a high-density polyethylene (HDPE) and a Ziegler linear low-density polyethylene (LLDPE), the HDPE and a metallocene linear-low density polyethylene (mLLDPE), and the HDPE and a long-chain branched high pressure low-density polyethylene (LDPE) were observed by scanning electron microscopy. In the interface of the HDPE-LLLDPE weld, lamellae continuing between both the polyethylene phases and spherulites extending over both the phases were observed. On the other hand, such morphology was not observed in the HDPE LDPE weld. The HDPE-mLLDPE weld interface exhibited the morphology of lamellae continuing between both the phases, but did not show spherulites extending over both the phases.View full abstractDownload PDF (2337K)
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