A compositional study of the morphology of 18-armed poly(styrene-isoprene) star block copolymers

Herman, Doreen S.; Kinning, David J.; Thomas, Edwin L.; Fetters, Lewis J.

doi:10.1021/ma00177a050

Cited by 75 publications

(53 citation statements)

References 35 publications

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“…The formation of self-assembled structures is driven by the microphase separation of different blocks of PS-SIS competing with the chemical linking between them. The findings observed here are consistent with those of the previous studies that have examined the effect of the volume ratio f PS of the block copolymers on a variety of copolymer morphologies [25,[51][52][53][54][55][56].…”

Section: Characterization Of Composite Filmssupporting

confidence: 91%

Enthalpy-driven selective loading of CdSe 0.75 S 0.25 nanoalloys in triblock copolymer polystyrene- b -polyisoprene- b -polystyrene

Aşkın¹,

Çeçen²,

Ünlütürk³

et al. 2016

Materials Today Communications

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a b s t r a c tCdSe 0.75 S 0.25 nanoalloys were blended with asymmetric triblock copolymer of polystyrene-bpolyisoprene-b-polystyrene(PS-SIS) in tetrahydrofuran. The fraction of styrene block varies from 14 to 22% with respect to isoprene by mass. The morphology of the copolymer cast film experiences a phase change from cylinder to lamella. CdSe 0.75 S 0.25 nanoalloys were prepared by two-phase method. The surface of the nanoalloys was capped by either oleic acid (OA) or n-tri-octylphosphonic acid (TOPO) in situ. The mean diameter of the alloyed particles is around 12 nm in both systems. The chemical nature of the nanoalloy surface was found to influence the dispersion of the particles over polymer volume. The size of the nanoalloy domains in PS is 50 nm, on average, consisting of approximately 0.7 wt% nanoalloys. However, the size of the nanoalloy domains is smaller when they are loaded into PS-SIS. The structure formation is predominantly determined by enthalpic compatibilization. Atomic force microscopy results suggest that the nanoalloys capped with TOPO sequester into PS-rich domains and enlarge the domain. On the other hand, the ones capped with OA prefer to locate in polyisoprene domains. The increase of particles over 1.0 wt% distorts the lamella structure.

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Section: Characterization Of Composite Filmssupporting

confidence: 91%

Enthalpy-driven selective loading of CdSe 0.75 S 0.25 nanoalloys in triblock copolymer polystyrene- b -polyisoprene- b -polystyrene

Aşkın¹,

Çeçen²,

Ünlütürk³

et al. 2016

Materials Today Communications

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“…Such a phenomenon is consistently observed and governed especially by the hydrophobic-hydrophilic balance, but the stability is affected by other external variables, for example, temperature, architecture, and terminal groups. 35,38,41,[148][149][150][151][152] Except for one compound, all amphiphilic POSS-M compounds eventually formed a uniform LB monolayer at a high surface pressure. At the highest surface pressure, the overall morphology is eventually dominated by the crowding of the POSS-M cores and alkyl branches.…”

Section: Reviewmentioning

confidence: 99%

“…33,34 Unique morphologies were found in branched and star block copolymers that are not observed for linear block copolymers. [35][36][37][38][39] At the air-water interface, the hydrophobic chains collapse into globules while the hydrophilic chains spreads out to form a brush-like or a flat (pancake-like) structures. [40][41][42][43][44][45][46][47] Hyperbranched molecules possess a tree-like structure similar to that of dendrimers with the same enhancement in chemical and physical properties but at a great reduction in cost and time of synthesis when compared with dendrimers.…”

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confidence: 99%

Assembling hyperbranched polymerics

Peleshanko¹,

Tsukruk²

2011

J Polym Sci B Polym Phys

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A condensed overview discusses the existing grafting approaches and the surface behavior of various hyperbranched polymers. We focus on the recent strategies and corresponding characterization of the resulting surface morphologies and structures with a number of relevant recent results from the authors' own research and existing literature. Some results discussed here are important for prospective applications of hyperbranched polymers in biomedical fields, for resistive coatings, tough blends, and reinforced nanocomposites are briefly summarized as well. V C 2011 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 50: 83-100, 2012 KEYWORDS: adsorption; hyperbranched; LB films; structural characterization; surfaces INTRODUCTION This publication presents a condensed overview of the existing grafting approaches as applied to hyperbranched polymers and discusses the surface morphologies of these polymers and corresponding composites and coatings. We mostly focus on the recent strategies and corresponding characterization of the resulting surface morphologies and structures developed in the authors' group with some relevant examples from current literature. A number of relevant results are also included here especially in relation to recent developments related to novel synthetic approaches of hyperbranched molecules as well as emerging applications of hyperbranched polymers and coatings for biomedical purposes, as resistive coatings, tough blends, and reinforced nanocomposites. Some comprehensive recent reviews on highly branched polymers, which are focused mainly on synthetic aspects can be found in literature.

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“…(AB) n stars are best prepared by coupling of (AB) n star copolymers were prepared by copolymerizaanionic living diblock copolymers with multifunctional election of PS-block-PI diblock anions with DVB (Merck; 65%, trophilic coupling agents such as multifunctional chlorosim-/p-isomer Å 2; 35%, ethylstyrene) in benzene. This solulane compounds (1)(2)(3). It is, however, difficult to extend tion was stirred at 20ЊC for 24 h, and the temperature was the functionality of the (AB) n stars with these compounds.…”

Section: Methodsmentioning

confidence: 99%

Structural Ordering in (AB)nStar Copolymer Solutions

Uchida

Ichimura

Ishizu

1998

Journal of Colloid and Interface Science

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SAXS measurements that the star copolymers formed the (AB) n -type star copolymers (arm numbers n Å 14 and 16; poly-lattice with a body-centered cubic (BCC) structure near the isoprene blocks Å 23-24 mol%) were prepared by anionic copoly-overlap threshold (C*) (7). The C* is defined as a region merization of polystyrene-block-polyisoprene diblock anions with of crossover between the dilute polymer solution where the divinylbenzene. The structural ordering of such star-block copoly-coils are separate and the more concentrated solution region mers was investigated through small-angle X-ray scattering and where the coils overlap. At the C* the coils begins to be electron microscopy. (AB) n -type stars formed a body-centered cudensely packed. However, the ordering process of (AB) n bic (BCC) structure near the overlap threshold (C*). This strucstars through the C* into bulk film is not unclarified. ture changed to a mixed lattice of BCC and face-centered cubicIn this paper, we prepared the (AB) n star-block polymers (FCC) structure with increasing polymer concentration. Near the bulk, such stars formed a FCC structure. It was concluded that having many arms (n Å 14 and 16) by copolymerization of (AB) n -type stars led to hierarchical transformation of the cubic PS-block-PI diblock anions with DVB. The self-micellizalattices from the C* threshold into a continuous film. ᭧ 1998 tion behavior was investigated by dynamic light scattering. Academic PressWe also examined the process of structural ordering for star-

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A compositional study of the morphology of 18-armed poly(styrene-isoprene) star block copolymers

Cited by 75 publications

References 35 publications

Enthalpy-driven selective loading of CdSe 0.75 S 0.25 nanoalloys in triblock copolymer polystyrene- b -polyisoprene- b -polystyrene

Enthalpy-driven selective loading of CdSe 0.75 S 0.25 nanoalloys in triblock copolymer polystyrene- b -polyisoprene- b -polystyrene

Assembling hyperbranched polymerics

Structural Ordering in (AB)nStar Copolymer Solutions

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