Nucleation and Crystallization in Diblock and Triblock Copolymers

Müller, Alejandro J.; Balsamo, Vittoria; Arnal, María L.

doi:10.1007/12_001

Cited by 282 publications

(367 citation statements)

References 191 publications

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“…With the rapid development of polymer synthesis strategy, various block copolymers with desired structures were obtained, and at the same time, the crystallization behavior for these copolymers was investigated accordingly [1][2][3][4][5]. Block copolymers, consisting of both crystalline and amorphous segments were widely recognized that their crystallization processes and the resulting crystal morphologies can be significantly influenced by microphase separation in melt [6,7].…”

Section: Introductionmentioning

confidence: 99%

Poly(ethylene glycol)-poly(tetrahydrofuran)-poly(ethylene glycol) triblock copolymer : Synthesis, crystallization behavior and novel morphology

Wang¹,

Fan²,

Tian³

et al. 2013

Express Polym. Lett.

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Abstract. Poly(ethylene glycol)-poly(tetrahydrofuran)-poly(ethylene glycol) (PEG-PTHF-PEG) triblock copolymer was synthesized by ring-opening polymerization of ethylene oxide using sodium alcoholate of PTHF as the macroinitiator. Its crystallization behavior and formation mechanisms of different crystal structures were studied. The study showed that the molecular weight of PEG-PTHF-PEG exhibited a significant effect on its crystallization: that is, with the increase of the copolymer's molecular weight, the crystallizability of PTHF blocks decreased gradually, which led to the transition of copolymer from crystalline-crystalline to crystalline-amorphous. By adjusting the total molecular weight of triblock copolymer, the crystallization process can be effectively controlled, and as a result, different spherulite structures were obtained. Particularly, when PTHF blocks became amorphous, novel double concentric spherulites were observed. The morphological structures were studied by differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FTIR), scanning electron microscope (SEM), polarized optical microscopy (POM), and its crystalline process was investigated.

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Section: Introductionmentioning

confidence: 99%

Poly(ethylene glycol)-poly(tetrahydrofuran)-poly(ethylene glycol) triblock copolymer : Synthesis, crystallization behavior and novel morphology

Wang¹,

Fan²,

Tian³

et al. 2013

Express Polym. Lett.

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“…It is well known that two kinds of crystallized morphology are formed in the system depending on the segregation strength of existing microdomain structures, mobility (or glass transition) of amorphous blocks, or crystallization rate (or degree of supercooling). 1,2 When the microdomain structure is not stable against the crystallization, it is replaced by a lamellar morphology, an alternating structure consisting of lamellar crystals and amorphous layers, in which the amorphous blocks are sandwiched between lamellar crystals. 3,4 When the microdomain structure is enough stable against the crystallization, on the other hand, it is completely preserved through the crystallization process to yield a crystallized microdomain structure.…”

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confidence: 99%

Dynamic Mechanical Study of Block Copolymer Crystallization Confined within Spherical Nanodomains

Nojima

Inokawa

Kawamura

et al. 2008

Polym J

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We have measured the thermal and dynamic mechanical properties of a crystalline-amorphous diblock copolymer, poly("-caprolactone)-block-polybutadiene (PCL-b-PB), in which the crystallization of PCL blocks was completely confined within spherical domains. DSC results showed that the crystallization behavior of PCL blocks was substantially different from that of crystalline homopolymers, and similar to that usually observed in other spherically confined crystalline blocks. The result of dynamic mechanical measurements clearly showed that the crystallization within each domain occurred independently to immediately yield crystallized rigid domains, indicating that crystal nucleation drives the total crystallization in this system. It is demonstrated that the dynamic mechanical measurement is an alternative method to pursue the spherically confined crystallization.KEY WORDS: Crystalline-amorphous Diblock Copolymer / Spherical Nanodomain / Confined Crystallization / Dynamic Mechanical Measurements /Crystalline-amorphous diblock copolymers show a unique crystallization behavior when they are quenched from a microphase-separated melt into low temperatures. It is well known that two kinds of crystallized morphology are formed in the system depending on the segregation strength of existing microdomain structures, mobility (or glass transition) of amorphous blocks, or crystallization rate (or degree of supercooling).1,2 When the microdomain structure is not stable against the crystallization, it is replaced by a lamellar morphology, an alternating structure consisting of lamellar crystals and amorphous layers, in which the amorphous blocks are sandwiched between lamellar crystals.3,4 When the microdomain structure is enough stable against the crystallization, on the other hand, it is completely preserved through the crystallization process to yield a crystallized microdomain structure. 5,6When crystalline blocks form (strongly segregated) spherical domains surrounded by amorphous blocks in high molecular weight diblocks, they crystallize within it. The crystallization behavior and resulting morphology for this case have extensively been studied so far 5-17 mainly by small-angle X-ray scattering (SAXS) and/or differential scanning calorimetry (DSC) techniques. The crystallization behavior was found to be extremely different from that of crystalline homopolymers; the crystallinity development did not show a sigmoid change usually observed in homopolymer crystallization with increasing crystallization time t c . Alternatively it was reasonably approximated by a first-order kinetics, that is, the crystallization rate was proportional to the volume fraction of uncrystallized blocks existing in the system at t c . These experimental facts lead to a conclusion that the crystallization occurs independently within each domain. Therefore, the nucleation in individual domain drives the total crystallization process, because the crystal growth is considered to be extremely fast.Reiter et al. directly confirmed this conclusion by using...

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“…In homopolymers, chain folding leads to metastable structures as imposed by the crystallization kinetics. On the other hand, chain folding in diblocks is determined by the number of OPEN ACCESS the folds that can be controlled by the size of the second, non-crystallizable block [1,2]. Coupling and competitive factors among different phase transitions of self-organizing polymers have been widely maneuvered to fabricate ordered structures at different length scales and may hold the key to the development of new structures needed for advanced materials [3].…”

Section: Introductionmentioning

confidence: 99%

Crystallization Behaviors and Structure Transitions of Biocompatible and Biodegradable Diblock Copolymers

Xue

Jiang

2014

Polymers

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Biocompatible and biodegradable block copolymers (BBCPs) containing crystalline blocks become increasingly important in polymer science, and have great potential applications in polymer materials. Crystallization in polymers is accompanied by the adoption of an extended conformation, or often by chain folding. It is important to distinguish between crystallization in homopolymers and in block copolymers. In homopolymers, chain folding leads to metastable structures introduced by the crystallization kinetics. In contrast, equilibrium chain folding in diblocks can be achieved as the equilibrium number of the folds is controlled by the size of the second block. The structures of BBCPs, which are determined by the competition between crystallization, microphase separation, kinetics and processing, have a tremendous influence on the final properties and applications. In this review, we present the recent advances on crystalline-crystalline diblock copolymer in our group.

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Nucleation and Crystallization in Diblock and Triblock Copolymers

Cited by 282 publications

References 191 publications

Poly(ethylene glycol)-poly(tetrahydrofuran)-poly(ethylene glycol) triblock copolymer : Synthesis, crystallization behavior and novel morphology

Poly(ethylene glycol)-poly(tetrahydrofuran)-poly(ethylene glycol) triblock copolymer : Synthesis, crystallization behavior and novel morphology

Dynamic Mechanical Study of Block Copolymer Crystallization Confined within Spherical Nanodomains

Crystallization Behaviors and Structure Transitions of Biocompatible and Biodegradable Diblock Copolymers

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