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Copyright of Kobunshi Ronbunshu is the property of Society of Polymer Science and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Kobunshi Ronbunshu is the property of Society of Polymer Science and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This comprehensive paper reviews recent topics which are related to the "Synthesis of Various Block Copolymers via Precision Polymerizations with Application to Nano-Organizations" of our research group. The recent development of precision polymerization has provided us with versatile tools for the synthesis of a wide range of functional block copolymers with well-defined structures. The molecular dimensions influence the selfassemblies and dictate their products, such as micelle, nanocage, and vesicle. Thus, we have prepared appropriate block copolymers for such nanoorganizations without regard to polymerization fashion. Firstly, we describe the metal-free living cationic polymerization for vinyl ethers using HCl⋅Et2O without a complex metal catalyst. This allowed us to prepare the biocompatible/biodegradable block copolymer, polyvinyl alcohol-b-poly(ε-caprolactone). Secondly, the transformation of living cationic vinyl polymerization to reversible addition fragmentation chain transfer (RAFT) polymerization mediated by a carboxylic RAFT agent was investigated in order to prepare the novel block copolymers with both vinyl ether and a different block. The living cationic polymerization is initiated from a proton derived from the carboxylic RAFT agent, then, the RAFT group as a counteranion is recovered to propagating carbocation, followed by the RAFT polymerization. Using the transformation process, we prepared novel double thermoresponsive diblock copolymers, which formed micelles in water within a given temperature range. Thirdly, as an example of the robust nano-organization, shell cross-linked (SCL) micelles were prepared via either such a living cationic vinyl polymerization or atom transfer radical polymerization. In particular, if the target degree of cross-linking is sufficiently low, SCL nanocages can be obtained. For soft nanocapsules like the nanocage, we next investigated the RAFT dispersion polymerization. Macromolecular amphiphiles are known to form a wide range of nanostructures such as spheres, worms, and vesicles in solvents that are selective for one of the blocks. However, such self-assembly is usually limited to dilute copolymer solutions (< 1%). We show that diblock copolymer self-assembly is precisely controlled by sequential reorganization during in situ polymerization in concentrated aqueous solutions. The final particle morphology is controlled not only by the block ratio but also by the total solids concentration. The RAFT dispersion polymerization was applied to the synthesis of anisotropic particles, namely lumpy rods. In this review, these four subjects were highlighted. [ABSTRACT FROM AUTHOR]

Various block copolymers of an alicyclic vinyl ether with a stimuli-responsive vinyl ether were synthesized by living cationic polymerization in the presence of a weak Lewis base. The obtained copolymers had very narrow molecular weight distributions and could form free-standing films when they had an alicyclic segment of sufficient length. The design of the primary structures of the polymers and the control of the surface morphology were critical for controlling thermally responsive wettability transitions of the film surfaces. [ABSTRACT FROM AUTHOR]

Precision and efficient star-shaped polymer synthesis using fast living cationic polymerization was achieved with FeCl3, SnCl4, or GaCl3 in the presence of an added base. Addition of FeCl3 following the addition of a divinyl compound into living poly[isobutyl vinyl ether (VE)] mixture accelerated the polymer-linking reaction significantly and yielded a star polymer with narrow molecular weight distribution (MWD) and high yield (Mw/Mn = 1.21, yield = 99%) within only 15 s. This system also accelerated the synthesis of star-shaped polymers containing polar functional pendants, e.g., poly(VE)s with malonate groups were linked efficiently using SnC14 in conjunction with THF in 30 min. Furthermore, heteroarm star polymers containing two types ofpoly(VE)s with malonate- and oxyethylene-pendants were prepared using SnCl4 in the presence of THF, rapidly and efficiently. [ABSTRACT FROM AUTHOR]

Heterogeneously catalyzed cationic polymerization of isobutyl vinyl ether was examined using a heteropoly acid combined with an added base. Polymerization using H3PW12O40 in the presence of a cyclic ether in dichloromethane induced only conventional cationic polymerization. In contrast, living polymerization was achieved in ethyl acetate in the presence of dimethyl sulfide at -30°C, producing polymers with very narrow molecular weight distributions. The Mn, values of the obtained polymers were in direct proportion to the monomer conversion and in good agreement with the calculated values, when one assumes that all three protons of H3PW12O40 initiated polymerization. MALDI-TOF-MS analysis demonstrated that the product polymer had the structures derived from only initiation with a proton and termination with methanol, terminator. [ABSTRACT FROM AUTHOR]

Novel N-substituted maleimides bearing an L-phenylalanine allyl ester or allyl amide as an N-substituent: allyl ester ((S) -APAMI), allyl amide ((S)-AAPAMI) and diallyl amide ((S)-DAAPAMI) were synthesized from maleic anhydride, L-phenylalanine, allyl alcohol, allyl amine and diallyl amine. Asymmetric polymerizations of maleimide monomers were performed with organometal/chiral ligands to obtain optically active polymers. The polymers obtained by anionic polymerizations showed specific optical rotations of [α]43525 = -91.8°~ -352.8°. The specific optical rotations and CD spectral patterns of the polymers were different from those of the model compounds for the polymers. These differences indicated that asymmetric induction took place on the main chain in all polymerization systems. The chemicalbonded-type chiral stationary phase for HPLC prepared from the polymer resolved some racemates. [ABSTRACT FROM AUTHOR]

In this work, the first example of fabricating feature sizes less than 10 nm by using block copolymer lithography on an organic-inorganic hybrid block copolymer material is described. A unique class of well-defined block copolymers which contain polyhedral oligomeric silsesquioxane (POSS) was used for this achievement. Two POSS containing block copolymers (BCPs) with high a degree of polymerization of POSS and a narrow polydispersity index (PDI) were synthesized by living anionic polymerization of styrene (PS-b-PMAPOSS) or methyl methacrylate and methacrylate functionalized POSS (PMMA-b-PMAPOSS). Both BCPs indicate well-defined lamellar or cylinder microphase-separated domains. The excellent self-assembly characteristics of these BCPs in thin-films combined with the outstanding high contrast in etching resistance and etch selectivity between PS or PMMA and PMAPOSS blocks leads to well-ordered line or hexagonally packed hole structures with a hole diameter of 9 rim. A one step oxygen plasma exposure converts the soft mask into a hard mask. The synthetic flexibility and the simplicity and ease of the self-assembly and etching process make these materials very attractive for creating small feature sizes. [ABSTRACT FROM AUTHOR]

Benzyl cellulose (CBz) with a degree of substitution (DS) of ca.2 was synthesized from cellulose and benzyl chloride (BzCl), and three sorts of macroinitiators of chloroacetyl benzyl cellulose (CBz-CACl). Chloromethylbenzoyl benzyl cellulose (CBz-CMBCl), and dichloroacetyl benzyl cellulose (CBz-DCACl) used for ATRP were synthesized by using the CBz and the acid chlorides of chloroacetyl chloride (CACl), p-chloromethylbenzoyl chloride (CMBCl) and dichloroacetyl chloride (DCACl), respectively. The graft copolymerizations of methyl methacrylate (MMA) and styrene (St) via ATRP by using these macroinitiators were carried out. In the system of graft copolymers of poly((CBz-CACl)-g-MMA), the living character of the polymerization was confirmed by the relationship of the added monomer amounts to the molecular weights of the graft chains. The changes of the X-ray diffraction patterns and the surface morphologies caused by the modification of cellulose were seen from the XRD measurements of the graft copolymers and the SEM micrographs observations of the poly((CBz-CACl)-g-MMA)s, respectively. [ABSTRACT FROM AUTHOR]

In this paper, we have investigated the living anionic polymerization of styrene with anions newly produced by lithiation in the initiator systems containing s-BuLi, a ligand and an aromatic compound. The ligands used were N,N,N' ,N'-tetramethylethylenediamine (TMEDA), N,N,N' ,N" ,N"-pentamethyldiethylene-triamine (PMDETA, 1,1,4,7,10,10-hexamethyltriethylene-tetramine (HMTETA), and (- ) -spartein (SP), and the aromatic compounds were toluene, 4-methylbiphenyl (4MB), 1-methylnaphthalene (1MN), and 9-methylanthracene (9MA). It was found that the initiation systems containing the combinations of toluene/TMEDA, toluene/SP, and 4MB/TMEDA gave polystyrene with very narrow molecular weight distribution (MWD), while that containing 9MA resulted in very broad MWD. Furthermore, the increase in the number of nitrogen atoms in the ligands influenced the MWD. Polymerizations with the initiator systems containing p-xylene, 4,4'-dimethylbiphenyl, and di-p-tolylmethane were also investigated. [ABSTRACT FROM AUTHOR]

The cationic polymerization of isobutyl vinyl ether (IBVE) was examined using various Lewis acids in the presence of an excess of acetylacetone (acac). With EtAlCl2, TiCl4, and FeCl3, almost no polymerization proceeded when the acac concentration was over 0.5 M. In contrast, SnCl4, ZnCl2, and GaCl3 induced polymerization even at a higher acac concentration. Interestingly, SnCl4 produced polymers with a narrow molecular weight distribution (MWD). In addition, the number-average molecular weight (Mn) of the product polymers increased proportionally to the monomer conversion. It should also be noted that the Mn of the products varied inversely with the amounts of SnCl4. These results suggested that H+, which was generated by the coordination of an acac molecule with SnCl4, is the real initiator for the polymerization. [ABSTRACT FROM AUTHOR]