Volume 46 Issue 11, November 2014

This review introduces recent attempts in the photoalignment processes of liquid crystalline polymers focusing on the two aspects. First, the strategies to ensure effective in-plane alignment of the photoresponsive mesogens are summarized. Despite many investigations reported so far, the film systems have not been optimized for efficient photoreaction. Second, new photoalignable systems involving block copolymer frameworks such as surface-grafted polymers and block copolymer thin films are introduced. The photoalignment processes in such mesoscopic systems involve strong cooperative motions among different hierarchical size features. Based on these approaches, a new strategic platform, photoalignment via a command surface at the free surface, is further proposed.

Polyglycolic acid (PGA) is a novel biodegradable resin. To mass-produce high-molecular-weight PGA on an industrial scale, Kureha Corporation has developed a new process for obtaining high yields of the intermediate glycolide (GL) with high levels of purity. Using the obtained GL, we developed a method to polymerize high-molecular-weight PGA continuously. A commercial production plant is now in operation. We have also developed various new applications that utilize its characteristics. The use of PGA in shale gas and oil exploration is of interest because PGA can supply ultra-strong and biodegradable materials.

Low-molecular-weight compounds, which form physical gels, are called ‘gelators’ and have received a great amount of scientific and technological interest. The physical gelation by gelator results from non-covalent bonds, represented by hydrogen bond. Molecules of gelator are first self-assembled in cooling process, producing fibrous assemblies. Then, these fibrous assemblies form a three-dimensional network structure, and gelation occurs by trapping solvent in the networks. Fibrous assemblies can be observed by electron microscope. This is a transmission electron microscopy image of tetrachloromethane gel formed by N-octadecylamide of N-benzyloxycarbonyl-L-isoleucine.

Bio-based amphiphilic polymers having a helical hydrophobic unit have been extensively studied on molecular assemblies and their morphology. Molecular assemblies having complex morphologies could be prepared by using the specific characters of the helical unit, and the unique self-assembling methodology was named as ‘patchwork self-assembling’. Further, application of the obtained molecular assemblies in medicinal fields was examined. Lactosome was accumulated at the targeted tumor region by the EPR effect, and therefore, expected to be an excellent nano-ordered carrier for drug and/or imaging agent delivery.

Novel core/shell-like structured ultrafine branch nanofibers were successfully fabricated by a phase-separation process using simple polymer blend (polyacrylonitrile (PAN) and fluorinated polyimide (PI)) solutions with electrospinning. The obtained core/shell-like structured branch nanofibrous membranes showed strong hydrophobicity based on the hydrophobic shell polymer and ultrafine branch nanostructures. This simple process could be used to prepare core/shell structured branch nanofibers composed of other blend polymers and would also provide novel opportunities for industrial applications, such as nanocoating, nanoreinforcement, nanocomposite, nanomedicine and a drug-release system.

We report the preparation of the conductive glasses based on organic−inorganic hybrids containing charge-transfer (CT) complexes with tetrathiafulvalene and 7,7,8,8-tetracyanoquinodimethane. The synthesized hybrids with relatively larger amounts of the loaded CT complexes can show the conductivity level similarly as a semiconductor (∼10⁻¹ S cm⁻¹). In addition, it was shown that the conductivity of the synthesized hybrids can be maintained during heating and dipping into water.

pH-responsive micelles of cholesteryl-modified poly (monomethyl itaconate)s (PMMI-Chol-C₆) with various amounts of cholesteryl substitutions were used as promising drug carriers. Polymeric micelles were stable at pH above 3 and low ionic strength. Transmission electron microscopy images and dynamic light scattering results of the P-77 and P-63 micelles showed regularly spherical micelles having 510 and 250 nm mean diameters with polydispersity indexes about 0.59 and 0.27, respectively. In vitro release studies of naproxen-loaded P-63 micelles demonstrated that release behavior was strongly pH dependent and introduced it as a novel pH-responsive nano-carrier for controlled drug release.

Ulva can overgrow and result in green tides around the world. It forms algal mats on the Wajiro tideland in Japan. The major polysaccharide of Ulva is ulvan, a sulfated glucurono-rhamno-xyloglycan. Ulvan was modified with three diisocyanate derivatives to yield urethane foam and its ability to remove Cu(II) ions from an aqueous solution was investigated. Notably, the foam could remove up to 72.7% of Cu(II) ions.

Recovery-after-crosslink behavior observed for PEA-A/PEA blends. For PEA in the matrix with molecular weight smaller than the entanglement molecular weight Me, the recovery was observed, whereas the shrinkage continues upon irradiation for PEA with larger molecular weight.

The long-term thermal stability of the attenuation of graded-index plastic optical fibers is strongly dependent on whether the glass transition temperature (T_g) of the cladding layer is higher than the environmental temperature. When fibers are exposed to temperatures higher than both the core and cladding T_g values, the core-cladding boundary fluctuates spatially and scatters light. However, our study indicates that the core is not necessarily required to be in a glassy state to maintain a flat, smooth interface as long as the cladding is in a glassy state.