Recnt advance in high grade functionalization of organic materials has been surveyed in view of functions and carrier materials. The function would be realized by combination of special action (dynamic-function), characteristic physical properties (static-function) and forms (shaping-function). Recently, more elaborated functions are required such as multifunctionalities in polymer catalysts and controlled functions in the slow release of drug. As the carrier of the functions, reactive polymers specially designed as intermediates have been developed as well as commercial polymers including many kinds of synthetic, natural and inorganic polymers. On the other hand, several new polymers which reveal functions based on their intrinsic characters were advanced as illustrated in biomedical polymers with microdomain structure, bilayer membranes and polymer crystals. Further, group-transfer polymerization, radical ring-opening polymerization, metathesis polymerization and soluble prepolymer for electroconductor are briefly explained as new methodologies applicable in designing the functional polymers.
Among various photofunctions exhibited by polymeric systems, photocatalysis, photovoltaic effects, and photoresponsiveness have attracted much attention in recent years. The present article reviews the recent research efforts directed to the better understanding of the photophysical and photochemical processes which underlie these photofunctions. The photofunctions are most efficiently brought about when thermal deactivation of excitation energy is prevented during the photophysical and photochemical processes. The degree of success in achieving desired photofunctions depends on whether the intrinsic nature of polymeric systems, e. g. amorphousness, is advantageous or disadvantageous for particular photofunctions. It is nevertheless emphasized that the continuing efforts of designing polymeric systems with increased sophistication may eventually overcome some of the difficulties now confronting us in using polymeric systems for particular photofunctions.
Recent progress in semiconductor devices has been remarkable. With the appearance of VLSI, production of devices has shifted from the 64K bit to the 256K bit. Reductions in size on the microfabrication have been achieved, from 2.5 μm for the 64K bit to 2.0 μm for the 256K bit. For 1 mega bit devices, further reduction to 1 μm has approached the limit for photoresist fabrication. Submicron fabrication will require special processing techniques. The following is a brief explanation of high resolution resists, including photoresist, Deep UV resist, electron beam resist, X-ray resist, and plasma-developable resist.
Biological and optically-active polymers show piezoelectricity when they have been subjected to a uniaxial drawing. Various polar polymers are both piezoelectric and pyroelectric if their dipole orientation is frozen-in after poling. Polyvinylidene fluoride and its copolymers are ferroelectric because their crystalline dipoles are switchable. They are therefore piezoelectric and pyroelectric. Polymeric materials belonging to these three categories are reviewed and basic mechanisms for these properties are discussed.
Optical resolution by liquid chromatography, particularly by high-performance liquid chromatography, has become a useful and important method for resolving enantiomers. In this review, the author discusses mainly the optical resolution by liquid chromatography with chiral polymers. The polymers include proteins, cellulose and other polysaccharide derivatives, cross-linked polymers with chiral cavity, optically active polyacrylamides, and poly (triphenylmethyl methacrylate). Chiral discrimination ability of the polymers depends very much on their second or higher order structure. Mostly, a higher chiral recognition ability is attained when the polymer exist as an order structure. This is a pronounced difference between the polymeric stationary phases and the stationary phases consisting of silica gel and chiral small molecules.
Recently, new type chelating resins which are highly selective for certain metal ions have been synthesized and these selective separation character of metal ions has been investigated. Also, metal pre-adsorbed ion exchange resins or chelating resins have been used for removal of some anions, such as As, F. This review presents recent studies on the recovery of precious metals such as U, Ga, In, Ge, V, Mo, Au, Pt, and Pd, on the removal of harmful metal ions such as Sb, Bi, Fe, Cr, Ca, Mg and on the removal of certain anions such as As, and F.
Highly guaranteed blood-compatible polymers are essentially fundamentals to advanced cardiovascular prostheses with blood-contacting circuits, which development has been increasingly demanded. In this article, mechanistic aspects of acquiring antithrombogenicity are firstly summarized. Well-accepted hypothetical mechanisms are divided into two major categories in principle ; one is “never-passivative or non-adherent” mechanism which is materialized by the formation of highly hydrated diffuse layer at a blood/material interface, and the other is “passivative” mechanism which could be achieved by a so-called “surface multiphasic or morphological” effect. The former one is formulated with physico-chemical approaches based on colloid and interface science, whereas the latter one needs biospecific control of complex nature of both biochemical and biological responses. Based on these working hypotheses or leading principles, recent trends of molecular design for antithrombogenic polymer surfaces are reviewed.
The recent studies on the research field of drug including polymer and its application were reviewed. Among them, various drugs were composed with natural and synthetic polymers of biodegradative or non-biodegradative using various means such as radiation polymerization, crosslinking, hot pressing and so on. The release profile of the drug from those polymers could be controlled widely by changing the polymer properties such as hydrophilicity, porosity, and so on. The micro-particle and the multi-layer composite were important for their specific release and targetting. Those techniques have been applied to local therapy, hormone therapy and targetting functions. Some of them reached the stage of clinical studies.
The functions of artificial membranes are mainly selective permeability or separation due to a sieving of free volume or pore based on the cohesive state of the polymer molecules. Furthermore, safety, mechanical properties and biocompatibility are important for medical use. The membranes for artificial lung, oxygen enrichment, artificial kidney, plasma separation, plasma component separation, drug delivery system and artificial skin are discussed on medical point of view.
Several new monomers which are effective to give adhesion to tooth substrates have been discussed based on the concept that monomers with hydrophobic and hydrophilic groups have biocompatibility with the tissues and promote the interpenetration of monomers into the substrates. The bond strength between dentin treated with 10 % citric acid and 3 % ferric chloride and 4-META/MMA-TBB resin was 18 MPa, but it decreased to 6 MPa when dentin was etched with phosphoric or citric acid. Ferric chloride in citric acid prevents the denaturation of collagen during the demineralization. Control of the higher structure of collagen is very important to get good bond to the dentin. The monomers interpenetrated into dentin or enamel and polymerized was confirmed by SEM observation on partially demineralized specimen of the bonded tissue. A HCl insoluble dentin or enamel band modified by the interpenetration in the subsurface of the tissue was identified. The band is a resin reinforced dentin or enamel and has better resistance against decalcification than the original. The band is a hybrid of natural tissues with biocompatible artificial materials.
Organic materials for optical use especially for optical fiber communication systems are described. Plastic optical fibers which are made through closed polymerization and fiber drawing apparatus are discussed. Deuterated poly-methyl methacrylate core optical fiber whose attenuation loss is 20 dB/km at 660 nm is explained. Light focusing plastic rods made by two step copolymerization technique or photo copolymerization technique are reviewed. Polymer optical waveguides such as dividers and star couplers using selective photo polymerization whose attenuation loss is 0.19 dB/cm at 0.83 μm are also described. Optical switches using liquid crystal as a cladding are explained and revealed to be effective to make 6 × 6 waveguide optical switches. Finally, nonlinear optical materials are described. Organic crystals such as p-nitro aniline are discussed and it is shown that hybridization with organic salts or inclusion complexes is effective to improve second order nonlinear optical effects.
During the last decade, proofs have been given to the theoretical anticipation in that organic materials, viz.linear polymers, can be as strong as metals and inorganic materials if molecules are arranged parallel in a highly crystalline state. They include highly oriented fibres of aromatic polyamides and polyethylene, the whisker-type single-crystal of polyoxymethylene, etc. which enjoys the Young's modulus of >100 GPa. In this article, discussion is made firstly on the theoretical Young's modulus of polymers with respect to their conformation and secondly on the super-molecular structure emphasizing the importance of the latter for the bulk properties. Then, various approaches to the development of high-strength materials are reviewed with reference to the recent progress, covering the su-per-drawing of flexible polymers, the liquid-crystal spinning of aromatic polymers, the direct synthesis of polymer crystals from monomers, etc.
Recent trend in thermally stable polymers for use in specialty engineering plastics and high performance fibers is reviewed with emphasis on the syntheses of various types of aromatic polymers such as aromatic hydrocarbon polymers, polyethers, polyesters, polyamides, polyimides, and other heterocyclic polymers.