Nagoya University · Materials Science
Professor Atsushi Takano's research lab specializes in the synthesis and characterization of complex polymer architectures, with a focus on block copolymers, star-shaped polymers, and cyclic polymers. The lab investigates their self-assembly behavior at the mesoscale, particularly in microphase-separated structures such as honeycomb and Archimedean tiling patterns, using advanced techniques like TEM, SANS, and HPLC. A key research direction involves understanding the conformational effects—such as loop and bridge formation—on the phase behavior and physical properties of polymers.
Figures are computed from collected data and may differ slightly.
Abstract The Archimedean tiling (3 2 .4.3.4) is a regular but complex polygonal assembly of equilateral triangles and squares. This tiling pattern with mesoscopic repeating distance has been found for an ABC star‐branched three‐component polymer composed of polyisoprene, polystyrene, and poly(2‐vinylpyridine). In this structure the environment of a molecule splits into multiple sites and two microdomains with different sizes and shapes are formed for one component. This complexity is the first o
Characteristic cylindrical microphase-separated structures have been found for three ABC star-shaped terpolymers. The samples are composed of polystyrene (S), polyisoprene (I), and poly(2-vinylpyridine) (P); their volume ratios of I:S:P are about 1:1:0.7, 1:1:1.2, and 1:1:1.9, respectively, three components being connected at one branch point. From three-dimensional morphological observation by TEM combined with electron computerized tomography, a terpolymer with volume ratio of 1:1:0.7 shows ho
Ring polystyrenes (PSs) were synthesized by anionic polymerization technique and purified with preparative size-exclusion chromatography (SEC). Seven ring PSs with their weight-average molecular weight (Mw) ranging from 17k to 570k were prepared and they were confirmed to have high purities all over 96% by liquid chromatography at the chromatographic critical condition (LCCC) analyses. Their radii of gyration (Rgs) were determined in benzene-d6 as a good solvent and in cyclohexane-d12 or cyclohe
To determine the loop/bridge ratio of an ABA triblock copolymer, dynamic viscoelastic measurements were carried out using a polystyrene-block-polyisoprene-block-polystyrene triblock copolymer (SIS), a cyclic SI diblock copolymer (cyclic-SI), and a polystyrene-block-polyisoprene-block-poly(2-vinylpyridine) triblock copolymer (SIP), which were carefully synthesized by the anionic polymerization technique. The three copolymers show similar microphase-separated structures having spherical domains of
Cyclization reaction product synthesized by the end-to-end ring closure reaction of a telechelic polystyrene with molecular weight of 38K in extremely dilute conditions was carefully characterized by using two kinds of HPLC techniques, that is, liquid chromatography at the critical condition (LCCC) and size exclusion chromatography (SEC). First, the cyclization reaction product was coarsely separated into linear species and cyclic ones by LCCC; second, each fraction was further separated by high
Three polystyrene-block-polyisoprene-block-polystyrenes (SIS) with different compositions were prepared and cyclized by the coupling reaction between two end groups on the same molecules. Ring-shaped polystyrene-block-polyisoprenes (SI) were isolated from the coupling products by GPC fractionation. They were ozonized in order to decompose the polyisoprene blocks selectively referring to the linear molecule. GPC analysis of the decomposed products obtained by ozonolysis quantitatively confirmed t
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