Hot Topics

Vol. 60, No. 4, April (2011)

Large-Area Molecular Ordering Leads to the Conversion of Light Energy into Mechanical Force
Takanori FUKUSHIMA, Nobuhiko HOSONO, and Takuzo AIDA
RIKEN Advanced Science Institute

Upon one-step hot pressing with uniaxially stretched Teflon sheets, a polymer brush, consisting of a polymethacrylate backbone wrapped with densely grafted paraffinic side chains containing three azobenzene units, self-assembles to form a free-standing film, where the backbone aligns homeotropically to the film plane, while the side chains align horizontally along the drawing direction of the Teflon sheets. Such a remarkable molecular ordering arises from translation of a 1D molecular order of the Teflon sheet into a 3D molecular order of the bulk polymer structure, which propagates macroscopically from the interface on both sides of the film. This finding allowed us to develop a conceptually new photoactuating polymer film, where a photoinduced deformation of the oriented side chains upsets and recovers a balance between the competing strains on the front and back sides of the film.
Science 2010, 330, 808.

Charge-by-Charge Assembly: New Strategy to Form Dimension-Controlled Organized Structures
Hiromitsu MAEDA1,2
1Institute of Science and Engineering, Ritsumeikan University, 2PRESTO, JST
Stimuli-responsive macromolecular systems comprising p-conjugated components are fascinating due to the formation of electronically tunable materials. In order to fabricate ion-responsive macromolecules, it is essential to design and synthesize the appropriate building molecules, which have efficient binding sites for charged species. Among p-conjugated anion receptors, boron complexes of 1,3-dipyrrolyl-1,3-propanediones have been found to be useful building units of supramolecular assemblies, such as anion-responsive supramolecular gels and liquid crystals, and of covalently linked receptor oligomers that exhibit anion-driven folding behaviors. The fairly planar and emissive pyrrole-based anion-responsive molecules provide new properties and concepts such as charge-by-charge assembly on the basis of the interactions worked in charged species.
Polymer Preprints, Japan, 2010, 59, 4050.
Angew. Chem., Int. Ed., 2010, 49, 10079.

Fabrication of 3D Liposomal Array for Potential Biomedical Applications
Yoshihiro SASAKI, Keita ABE, and Kazunari AKIYOSHI
Institute of Biomaterials and Bioengineering, Tokyo Medical and Dental University
Microchemical chips, which can handle multiple chemical processes including analysis, synthesis and extraction within a very small device, have attracted considerable attentions. The objective of this study is to construct three-dimensional liposomal arrays using self-assembling process for fabrication of bio/chemical chips formed with lipid bilayer membranes in place of glasses and silicones widely employed in current technology. In this study, we constructed 2D- and 3D-array of the liposomes by utilizing highly selective DNA hybridization, in which liposomes are integrated in bulk solution and at the solid-liquid interface. This technology has potential utility for next-generation nano system and wide spread applications in proteomics and personalized medicine.
Polymer Preprints, Japan 2010, 59, 5088.

Element-Based Hybrid Polymers
Yoshiki CHUJO
Department of Polymer Chemistry, Kyoto University
A new concept, "element-based hybrid polymers", is proposed. Based on the unique characteristics of hetero-elements, the development of various kinds of new interesting hybrid materials are expected to emerge. Exploration of the scope of new elements-containing hybrid polymers should be a useful approach for the preparation of such polymers. Another methodology might be a combination of organic polymers and inorganic materials at molecular- or nano-level. As exemplary prototypes, two materials are demonstrated in the present paper; "organic-inorganic nano-hybrid materials" and "conjugated polymers containing inorganic elements". The former was prepared mainly by the sol-gel method in the presence of organic polymers by designing specific interactions between two different matrices. In the latter case, the incorporation of inorganic elements or inorganic building blocks into the main chain of the organic polymers is illustrating the key point.
Polymer Preprints, Japan 2010, 59, 4242.

Realignment of the Definition of Biomimetics
Tomonaga YOSHIDA
New Energy and Industrial Technology Development Organization
Problems concerning global loads, such as those related to the environment, energy and natural resources, are attracting increasing attention worldwide. In addition, the loss of biodiversity has recently become a concern of many people. These problems need to be solved to realize a sustainable recycling society. On the other hand, a tradeoff has emerged between economic development and environmental issues. In this regard, people are becoming more and more interested in biomimetics as a means of alleviating this tradeoff. However, biomimetics is not a new concept. Therefore, similar terms have become prevalent and the way of thinking regarding biomimetics is not consistent around the world. Under such circumstances, we would like to propose a realignment of the definition of biomimetics.
Polymer Preprints, Japan 2010, 59, 4496.

Preparation of Shell Cross-Linked Polymersome
Shin-ichi YUSA
Department of Materials Science and Chemistry, University of Hyogo
To prepare shell cross-linked polymersome, we used a pH-responsive anionic diblock copolymer as a mold. The mold micelle can be dissociated at basic pH. The diblock copolymer composed of a PEG block and a cationic block containing a small amount of photo-cross-linkable pendent group was absorbed to the surface of the pH-responsive mold micelle to form a core-shell-corona onion-like micelle. The shell of the onion-like micelle is composed of a polyion complex, which can be cross-linked by UV-irradiation. After the cross-linking, to dissociate the mold, the solution pH was changed to basic. Furthermore, the solution was dialyzed against high ionic strength aqueous solution to eliminate electrostatic interaction, and subsequently against pure water to remove the dissociated anionic diblock copolymer.
Polymer Preprints, Japan 2010, 59, 4364.