Morphologies of microphase-separated conformationally asymmetric diblock copolymers

Pochan, Darrin J.; Gido, Samuel P.; Jian, Zhou; Mays, Jimmy W.; Whitmore, M. D.; Ryan, Anthony J.

doi:10.1002/(sici)1099-0488(19971130)35:16<2629::aid-polb6>3.0.co;2-k

Cited by 20 publications

(26 citation statements)

References 37 publications

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“…The thermodynamic implications of conformational asymmetry between the two blocks of diblock copolymers are considered to explain a lot of experimental results. 25,26 It is a commonplace to say that the properties of a copolymer depend not only on its global architecture and chemical composition but also on the local chemical structure of its monomeric units. Therefore, an important route in the precise control and theoretical prediction of molecular parameters required to achieve well-defined microphase-separated morphologies is connected with understanding the role of local polymer structure responsible for intra-and intermolecular interaction.…”

Section: Introductionmentioning

confidence: 99%

Microphase separation of diblock copolymers with amphiphilic segment

et al. 2009

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We present a statistical mechanical approach for predicting the self-assembled morphologies of amphiphilic diblock copolymers in the melt. We introduce two conformationally asymmetric linear copolymer models with a local structural asymmetry, one of a ''comb-tail'' type and another that we call ''continuous jackknife model.'' The copolymers consist of amphiphilic and ''monophilic'' (nonamphiphilic) blocks, which have different segmental volume and tend to segregate into subphases. Using a self-consistent field theory (SCFT) framework, we explore the phase diagrams for these copolymers and compare them with that known for conventional, conformationally symmetric diblock copolymers. To determine the impact of structural effects on the self-assembly of copolymer melts, copolymers with a variation in both molecular architecture and chemical composition, f, are studied for different values of the Flory-Huggins parameter, c. The composition dependence of the phase diagrams is shown to be basically determined by the conformational asymmetry. Remarkably, the stable lamellar structures exist even in the very compositionally asymmetric case, f < ¼. An interesting geometric distinction of the ''direct'' and ''inverse'' morphologies is introduced. The presence of an internal structure is found to influence the high c behavior, where a stable two-scale (structure-instructure) hexagonal morphology is found to be formed for some compositions. Therefore, the local chemical structure of monomer units can dictate the global morphology of copolymer melts.

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Section: Introductionmentioning

confidence: 99%

Microphase separation of diblock copolymers with amphiphilic segment

et al. 2009

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“…[7][8][9][10] TEM is now widely and routinely used in polymer science. For example, the morphology of block copolymers, [11][12][13][14][15][16][17][18][19] blend polymers, [20][21][22] dendrimers, [23][24][25] spun core/shell fibers, 26 copolymer latex particles, 27 graft-copolymers on natural rubber, 28 and composite particles of epoxy-polymers 29 have been studied using TEM.…”

Section: Introductionmentioning

confidence: 99%

“…Heavy-metal-containing compounds are used prior to TEM observation to selectively deposit electron-dense atoms on the sample. Uranyl acetate, [7][8][9][10]23,24 osmium tetroxide (OsO4), 11,16,19,20,22,26,28 ruthenium tetroxide (RuO4), [13][14][15]17,18,21,27 , and phosphotungstic acid (H3PW12O4) [29][30][31][32][33][34] are widely employed as stains. Even though uranyl acetate is a radioactive compound and both OsO4 and RuO4 are extremely toxic oxidizing agents that must be handled with utmost care, surprisingly little research effort has been dedicated to developing non-hazardous stains for TEM.…”

Section: Introductionmentioning

confidence: 99%

A Safe, Simple, and Facile Staining Method Using Polysiloxanes for High-Contrast Visualization of Gelator Aggregates by Transmission Electron Microscopy

Hanabusa

Nakashima

Funatsu

et al. 2018

Bulletin of the Chemical Society of Japan

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“…4 Such phase behavior and many other properties strongly depend on the conformation of the polymer in solution or bulk. 5 However, almost no data have been reported on the conformation of PCHD, probably because of the lack of well-defined and well-characterized samples. Here we report solution properties of PCHD in tetrahydrofuran (THF) and chloroform by multiangle laser light scattering, viscometry, and small-angle neutron scattering (SANS).…”

Section: Introductionmentioning

confidence: 99%