Chain elongation suppression of cyclic block copolymers in lamellar microphase-separated bulk

Matsushita, Yushu; Iwata, Hiroshi; Asari, Takeshi; Uchida, Toshiro; Brinke, G. ten; Takano, Atsushi

doi:10.1063/1.1760514

Cited by 31 publications

(32 citation statements)

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“…The difference between cyclic and linear polymers, in terms of molecular structure, is only the presence or the absence of chain ends. However, this small difference leads to various kinds of different physical properties, such as chain dimension in solution and bulk, 5,21,[27][28][29][30][31] glass transition temperatures, [32][33][34][35] viscoelasticity, 36,37 diffusion, [38][39][40][41][42][43] microphase-separated structures 44 and crystallization [45][46][47] among others. Hence, cyclic polymers are one of the ideal model polymers to use for understanding the effect of topology on the thermodynamics and molecular motion of polymers.…”

Section: Introductionmentioning

confidence: 99%

Direct observation and mutual diffusion of cyclic polymers

Kawaguchi

2013

Polym J

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A cyclic polymer is one of the ideal model polymers with which to investigate the effects of chain topology on the physical properties of polymers. In this review, I summarize my recent work demonstrating that the chain structure of cyclic polymers can be directly observed by atomic force microscopy (AFM) and that the mutual diffusion of cyclic polymers is faster than that of corresponding linear ones. For direct evidence of the cyclic structure, isolated molecules of cyclic poly(sodium styrenesulfonate), which was derived from cyclic polystyrene, were observed by AFM. The mutual diffusion of cyclic polystyrene/ cyclic deuterated polystyrene was investigated as a function of temperature and molecular weight by dynamic secondary ion mass spectroscopy. For the molecular weight of 113k, the mutual diffusion coefficient of cyclic polystyrene, D C , was approximately twofold larger than that of the corresponding linear polymer, D L , at all temperatures. Under an iso-free volume condition, the D C value was larger than the D L value for all the molecular weights. These results clearly show that the chain topology strongly affects the molecular motion of the whole chain.

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Section: Introductionmentioning

confidence: 99%

Direct observation and mutual diffusion of cyclic polymers

Kawaguchi

2013

Polym J

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“…TEM observations were carried out by adopting the same manner reported previously. 22 Figure 2 shows typical TEM images of the sample I 1.0 S 1.0 P 1.3 . It has been confirmed that three polymer chains branched at one junction point all show cylinder-based structure.…”

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confidence: 99%

A mesoscopic Archimedean tiling having a new complexity in an ABC star polymer

Takano

Kawashima

Noro

et al. 2005

J Polym Sci B Polym Phys

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156

175

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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 observation in complex polymer systems and can lead to a new type of mesoscale self-organization. The tiling pattern has been observed for the other materials on much shorter length-scale; therefore, the experimental fact observed in the present study is demonstrating that the complexity is universal over different hierarchies.

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“…Herein, the solid and hollow symbols (triangle, circle, and pentagram) represent the rod blocks played as the minor or major moiety in micelle, cylinder, and gyroid phases, respectively. Similar to the case of coil-coil diblock copolymers (no matter linear or cyclic case), 21,25,34,35 with varying block composition f, the morphology is transited from micelle to cylinder to lamellae, and then inversely from lamellar to cylindrical to micellar phase, respectively. There are some intermediate structures between lamellar and cylindrical phase regions, such as gyroid (G) and perforated lamellae (PL), which are observed commonly in experimental studies.…”

Section: Resultsmentioning

confidence: 82%

Self-assembly of cyclic rod-coil diblock copolymers

Chen

Zhang

et al. 2013

The Journal of Chemical Physics

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The phase behavior of cyclic rod-coil diblock copolymer melts is investigated by the dissipative particle dynamics simulation. In order to understand the effect of chain topological architecture better, we also study the linear rod-coil system. The comparison of the calculated phase diagrams between the two rod-coil copolymers reveals that the order-disorder transition point (χN)ODT for cyclic rod-coil diblock copolymers is always higher than that of equivalent linear rod-coil diblocks. In addition, the phase diagram for cyclic system is more "symmetrical," due to the topological constraint. Moreover, there are significant differences in the self-assembled overall morphologies and the local molecular arrangements. For example, frod = 0.5, both lamellar structures are formed while rod packing is different greatly in cyclic and linear cases. The lamellae with rods arranged coplanarly into bilayers occurs in cyclic rod-coil diblocks, while the lamellar structure with rods arranged end by end into interdigitated bilayers appears in linear counterpart. In both the lamellar phases, the domain size ratio of cyclic to linear diblocks is ranged from 0.63 to 0.70. This is attributed to that the cyclic architecture with the additional junction increases the contacts between incompatible blocks and prevents the coil chains from expanding as much as the linear cases. As frod = 0.7, the hexagonally packed cylinder is observed for cyclic rod-coil diblocks, while liquid-crystalline smectic A lamellar phase is formed in linear system. As a result, the cyclization of a linear rod-coil block copolymer can induce remarkable differences in the self-assembly behavior and also diversify its physical properties and applications greatly.

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Chain elongation suppression of cyclic block copolymers in lamellar microphase-separated bulk

Cited by 31 publications

References 30 publications

Direct observation and mutual diffusion of cyclic polymers

Direct observation and mutual diffusion of cyclic polymers

A mesoscopic Archimedean tiling having a new complexity in an ABC star polymer

Self-assembly of cyclic rod-coil diblock copolymers

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