Invited Review in 2012

This review describes the developments of self-assembled photonic crystals (PCs) of chiral liquid crystals (CLCs) and colloidal crystals (CCs) for laser applications. Both CLCs and CCs have intrinsic capabilities to spontaneously assemble 1D-PCs and 3D-PCs, respectively. By combining fluorescence dyes in the structures, the stimulated laser action can be generated by optical excitation. Moreover, the optically excited lasing is controllable by external stimuli due to their self-organization. This review highlights the research backgrounds of CLCs and CCs, as well as the experimental results of soft and tunable laser applications.

This article reviews recent findings on the optical, electro-optic, and optoelectronic properties of natural and chemically modified DNAs. This review specifically deals with photoluminescence and ET, lasing, NLO, organic light-emitting diode, and photovoltaic characteristics of various compositions based on natural and modified DNAs. Replacement of the Na⁺ counter-ions of natural DNA with functionalized cationic moieties is rapidly broadening the possible utilizations of DNA-based novel materials.

Poly (butylene succinate)(PBS) nanocomposites and PBS ionomer were prepared by in situ polymerization. This review focused on the effect of the modified clay, TS-1 zeolite and ionic group in PBS matrix on physical properties, rheological properties, crystallization behavior and biodegradability control.

Supramolecular polymer is broadly defined as any type of an assembly formed from one or more molecular components via reversible bonds; therefore, monomeric and polymeric states are in equilibrium over the relevant experimental timescale. Structural and dynamic properties of supramolecular polymers, including the degree of polymerization (DP), chain lifetime and conformational flexibility, are influenced by external stimuli; thus, these result in supramolecular ‘smart’ materials, which offer adaptivity that leads to easy fabrication, stimuli responsiveness and self-healing at the forefront of science and engineering. This review will focus on the recent developments in supramolecular polymers composed of discrete repeating units, as well as novel supramolecular materials produced by the interplay of supramolecular and polymer chemistry.

We have proposed the concept and significance of nano-alloyed polymer, which includes nano-dispersed domains, and have developed the biaxially stretched film with higher glass transition temperature and improved dimensional stability as compared with regular poly(ethylene terephthalate) film (Figures 1 and 2). Highly concentrated polyimide master batches are made at much lower temperature compared with regular processing temperature. The nano-alloyed film is obtained by film-making process having biaxial stretching and heat treatment. The nano-sized domains have an important role as pseudo-cross-linkage points, for demonstrating good drawing process ability and high orientation.

Based on the systematic classification and on the isomeric properties of polymer chain topologies, a variety of novel multicyclic macromolecular constructions has now been rationally designed and subsequently realized. In particular, an electrostatic self-assembly and covalent fixation process, optionally in conjunction with effective covalent linking chemistry, has been demonstrated as a new synthetic protocol for unprecedented polymers possessing multicyclic topologies.

The new ‘Sea/Island’ composite-spinning technology has solved the problem of unstable quality associated with conventional mass-production nanofibers. ‘Sea/island’ composite spinning achieves the high-strength polyester nanofiber based on conjugated (two components) spinning theory. The separation process between sea–islands components is successful with 1000 times faster in alkali solution resolution sea polymer than island polymer. Nanofiber has a very large surface area, absorption, distribution and filtration effect, which are suitable for a variety of applications, including functional sportswear, inner wear, skin-care products, filters, precision grinding cloth, and so on.

A retardation film consists of optical polymer to control polarized light by the oriented birefringence. One of the issues of the films is wide-banding of birefringence. We have researched a novel molecular design to control dispersion, and found that the wide-band properties appear in a narrow range near the birefringence zero point, which is determined by the volume fractions of the positive monomer units to the negative units. The wide-band retardation film has been industrialized using a novel co-PC with a fluorene ring based on the molecular design.

Pd complexes with diimine ligands promote controlled cyclopolymerization of 1,6-dienes and 1,6,11-trienes to afford the polymers containing 1,2-trans-cyclopentane groups with well-regulated stereochemistry. Copolymerization of the dienes with ethylene and α-olefins also proceeds to give functionalized polyolefins. The polymerization of the monomers with oligomethylene spacer yields the polymers with five-membered rings in accurate density and distribution along the polymer chain. 4-Alkylcyclopentenes and alkenylcyclohexanes also get polymerized by the Pd complex to afford polymers with 1,3-trans-cyclopentane groups and 1,4-trans-cyclohexane groups, respectively. Isotactic polymer of 4-alkylcyclopentenes show liquid crystalline properties.

Glycopolymers with pendant saccharides are biofunctional polymers that interact with saccharide recognition proteins. The glycopolymers show the strong molecular recognition ability owing to the multivalency. These polymers were prepared by the polymerization with sugar derivatives or by the saccharide addition to the polymer backbone. The glycopolymers can be applied for cell cultivation, drug delivery, and biosensing. The living radical polymerization provided the precise structure of glycopolymer, which was useful for analysis of the protein–saccharide interactions. The living radical polymerization also provided the hybrid biomaterials that can be used for biosensing and biomaterials.

Recent developments in artificial cutters for site-selective scission of single-stranded DNA are described. With the cutters composed of two oligonucleotide additives and Ce(IV)/EDTA, long single-stranded DNA can be selectively cut at target site and manipulated according to our needs.

Antifreeze proteins (AFPs) function as inhibitors of ice growth. Computer simulation studies have contributed to the understanding of the molecular-scale mechanism of ice growth inhibition by AFPs. For example, molecular dynamics simulations of a growing ice–water interface to which a winter flounder AFP for a {20\(\overline{2}\)1} pyramidal plane is bound have indicated that the growth rate of ice surrounding the AFP decreases drastically, owing to depression of the ice melting point through the Gibbs–Thomson effect.

Recent work is reviewed in which nanoporous polyethylene, derived from a polymeric bicontinuous microemulsion, is used as a nanocasting template in the synthesis of a catalogue of porous materials, including ceramics, thermosets, conducting polymers, and hierarchical inorganic and organic materials. Their structures replicate that of the bicontinuous microemulsion precursor with high fidelity, resulting in disordered and three-dimensionally continuous arrangements of multiple phases having a characteristic length scale of ∼100 nm.

We demonstrated that a method based on the analysis of both orientational birefringence and photoelastic birefringence is effective for designing polymers that are processed in a molten state and used in a glassy state. The designed polymer exhibits no birefringence for any orientation of the polymer main chains or under elastic deformation. Birefringence is close to zero even in injection-molded plates of the polymer. We have also shown that it is possible to compensate and control the birefringence of polymers using inorganic nanocrystals, and we have obtained valuable information on the optimal size of nanocrystals for compensation and control of birefringence.