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Volume 68, Issue 10
Displaying 1-5 of 5 articles from this issue
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Comprehensive Papers
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Shingo TAMESUE, Yoshinori TAKASHIMA, Hiroyasu YAMAGUCHI, Seiji SHINKAI ...Article type: Comprehensive Papers
2011 Volume 68 Issue 10 Pages 669-678
Published: 2011
Released on J-STAGE: October 25, 2011
JOURNAL FREE ACCESSToday, stimuli-responsive materials are paid much attention by researchers all over the world because they can be used in a very wide range of fields, such as drug delivery systems, sensor systems, actuators and so on. Although various stimuli-responsive materials including supramolecular structures were reported, there are only a few reports about photoresponsive supramolecular materials. One kind of a successful photoresponsive material is the photoresponsive organogel formed by using low molecular weight gelaters (LMWGs).
In this research, we present new photoresponsive supramolecular materials by mixing cyclodextrin modified host polymers and azobenzene modified guest polymers. Moreover, we report a new photoswitchable hydrogel including carbon nanotubes.
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Original Papers
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Kaoru ADACHI, Yasuyuki TEZUKA, Yasuhisa TSUKAHARAArticle type: Original Papers
2011 Volume 68 Issue 10 Pages 679-684
Published: 2011
Released on J-STAGE: October 25, 2011
JOURNAL FREE ACCESSA macrocyclic polyacrylate having a mesogenic 4-methoxybiphenyl group at each repeating unit was synthesized by ring closing metathesis reaction of linear telechelic polymer precursor having allyl end groups, which was synthesized by atom transfer radical polymerization of a corresponding acrylate monomer initiated with a difunctional initiator followed by an allylation reaction of the terminal bromide groups with allyltributylstannane. The obtained cyclic polymer was characterized by 1H NMR, MALDI-TOF MS and GPC. The thermal properties of the cyclic polymer and its linear counterpart were studied by DSC. The cyclic polymer showed a higher phase transition temperature and a narrower transition region compared to the linear counterpart, which might be due to the topological effect of the absence of terminal group in the cyclic polymer.
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Kazuya MIKI, Kazuhiro ISHIDA, Takahiro UNO, Takahito ITOH, Masataka KU ...Article type: Original Papers
2011 Volume 68 Issue 10 Pages 685-693
Published: 2011
Released on J-STAGE: October 25, 2011
JOURNAL FREE ACCESSA novel cyclic macromonomer based on a cyclic polyacrylic acid was prepared. Its radical copolymerization with N-isopropylacrylamide (NIPAAm) was carried out to obtain mechanically cross-linked poly(N-isopropylacrylamode) (PNIPAAm) with movable cross-linking points. The swelling ratio of the gel was found to be dependent on pH, indicating that the mobility of the cyclic polyacrylic acid on the polymer chain is responsible for swelling.
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Tsunaki KITAHARA, Shinichi YAMAZAKI, Kunio KIMURAArticle type: Original Papers
2011 Volume 68 Issue 10 Pages 694-701
Published: 2011
Released on J-STAGE: October 25, 2011
JOURNAL FREE ACCESSIn order to clarify the effects of entanglement species on nucleation of polymers, we studied the growth rate of spherulite G of cyclic and linear polyethylenes (C-PE and L-PE) from the melt as a function of degree of supercooling ΔT by means of polarizing optical microscope. We prepared several C-PEs with different weight average molecular weights Mw=9300, 43600 and 86500, and L-PE with Mw=44000. G of all the sample were obeyed the equation, G=G0 exp (−B/ΔT). B of C-PE gradually increased with increasing Mw. B is proportional to the surface free energy of the end surface of the nucleus, and this indicates that the regularity of folding surface increased with increasing Mw. We consider that topological constraint of cyclic polymer becomes large with decreasing Mw of the cyclic polymer. On the other hand, for C-PE and L-PE having almost the same Mw(=44 k), G0 of C-PE is much less than that of L-PE. Due to the topological constraint of cyclic polymer, we speculated that the adsorption mode on the crystal surface of C-PE is different than that of L-PE.
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Norihito MIYAGAWA, Ayumi KAWASAKI, Masahiro WATANABE, Masahiro OGAWA, ...Article type: Original Papers
2011 Volume 68 Issue 10 Pages 702-709
Published: 2011
Released on J-STAGE: October 25, 2011
JOURNAL FREE ACCESSRecently, reports about supramolecular polymers containing mechanical linkages have attracted much attention, in which the synthetic study of main chain-type polyrotaxanes have been extensively reported. However, there are several problems concerning the synthesis of polyrotaxane with respect to the control of coverage ratio of polyrotaxane and the low applicability of the polymer structure. On the basis of a background, this paper describes the synthesis of a polyrotaxane via the metal-template method. As a result, we developed two efficient synthetic protocols of well-defined polyrotaxane exploiting both a Pd-templated macrocycle and a pyridine-containing axle component; (i) a polycondensation to afford various polymer axle-containing polyrotaxanes and (ii) a threading method enabling the control of the coverage ratio.
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