Self-Assembly of Semiflexible-Coil Chiral Block Copolymers under Various Segregation Strengths with Multiple Secondary Interactions

Yang, Kai-Chieh; Chiu, Po-Ting; Tsai, Hsiu-Wen; Ho, Rong‐Ming

doi:10.1021/acs.macromol.1c01447

Cited by 11 publications

(9 citation statements)

References 42 publications

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“…The finding might be a sign of the asymmetric phase diagram due to the high conformational asymmetry parameter that thus enlarges the forming regions of network and cylinder phases. Similarly, the highly asymmetric phase diagram has been found in PS–PLLA recently where the region of the H* phase is enlarged to over a PLLA volume fraction of 0.50 and PLLA remains as the core …”

Section: Resultssupporting

confidence: 60%

“…Similarly, the highly asymmetric phase diagram has been found in PS−PLLA recently where the region of the H* phase is enlarged to over a PLLA volume fraction of 0.50 and PLLA remains as the core. 13 Interestingly, further increasing the PLLA volume fraction will enhance the rod−rod interaction of rigid PLLA chains, giving an irregular lamellar-like structure in the PLLA-rich region. The formation of a lamellar structure might suggest the cancelation of the spontaneous curvature toward the PLLA microdomain in the PLLA-rich region for the balance between compositional asymmetry and conformational asymmetry.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

“…The experimental results also provide insights into the inter-chain chiral interaction, suggesting the universal behavior of the chirality effect on BCP self-assembly to give the formation of H* from BCPs* . Moreover, the phase diagram is highly asymmetric in volume fraction with an irregular lamellar-like structure observed in the strong segregation region due to the mutual effects of conformational asymmetry and the chirality effect as well as rod–rod interactions, giving curvatures on the basis of the lamellar microdomain . In contrast to AB diblock copolymers, the phase behaviors in the ABC triblock system are much more complicated, at which the self-assembled phases will depend on two independent composition variables from f A v , f B v , and f C v ( f C v = 1 – f A v – f B v ), three interaction parameters (χ AB , χ BC , and χ AC ), and three Kuhn lengths ( b A , b B , and b C ).…”

Section: Introductionmentioning

confidence: 94%

“…12 Moreover, the phase diagram is highly asymmetric in volume fraction with an irregular lamellar-like structure observed in the strong segregation region due to the mutual effects of conformational asymmetry and the chirality effect as well as rod−rod interactions, giving curvatures on the basis of the lamellar microdomain. 13 In contrast to AB diblock copolymers, the phase behaviors in the ABC triblock system are much more complicated, at which the self-assembled phases will depend on two independent composition variables from f A v , f B v , and…”

Section: ■ Introductionmentioning

confidence: 99%

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Curving and Twisting in Self-Assembly of Triblock Terpolymers Driven by a Chiral End Block

et al. 2022

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A series of triblock terpolymers composed of a chiral end block, poly(L-lactide) (PLLA) (designated as chiral triblock terpolymers), are designed and synthesized for self-assembly. The chiral PLLA block can contribute the chirality effect for the twisting of microphase-separated domains. By attaching an asymmetric amount of the chiral block to a symmetric diblock of polyisoprene-bpolystyrene (PI-PS), compositional asymmetry can be created for the curving of microphase-separated domains. Moreover, the difference in persistence lengths of PS and PLLA blocks can give conformational asymmetry to the curving. With the combined effects of twisting and curving, the curvature at the saddle surface of microphase-separated domains might become significant to give the formation of a network phase. Consequently, a transformation from two-domain lamellae to core−shell network phases, then to a core−shell cylinder phase, and finally to a three-domain lamellar phase with undulation due to the rod−rod interaction with the chirality effect from the semiflexible PLLA, can be found in the isopleths of the triblocks. Interestingly, a core−shell double diamond phase could be found near the center of the ternary phase diagram; we speculate that the alleviation of packing frustration in the core of the self-assembled microdomain is attributed to the character of semiflexible PLLA. Accordingly, the phase window of network formation can be enlarged by the combined effects of compositional asymmetry, conformational asymmetry, and chirality.

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Section: Resultssupporting

confidence: 60%

Section: ■ Results and Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 94%

Section: ■ Introductionmentioning

confidence: 99%

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Curving and Twisting in Self-Assembly of Triblock Terpolymers Driven by a Chiral End Block

et al. 2022

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“…We now turn to the polypeptide-based polymers for which some experimental conformation metrics are available for the polystyrene-b-poly(L-lactide), where PS is the achiral block while PLLA is chiral. Yang et al 47 , which is also the ratio of persistence lengths. Spectroscopic measurements on crystalline PLLA 48 suggest that the number of monomers per helical turn is between 3 and 3.33.…”

Section: Macromoleculesmentioning

confidence: 99%

A Tunable, Particle-Based Model for the Diverse Conformations Exhibited by Chiral Homopolymers

2022

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Chiral block copolymers capable of hierarchical self-assembly can also exhibit chirality transferthe transfer of chirality at the monomer or conformational scale to the self-assembly. Prior studies focused on experimental and theoretical methods that are unable to fully decouple the thermodynamic origins of chirality transfer and necessitate the development of particle-based models that can be used to quantify intrachain, interchain, and entropic contributions. With this goal in mind, in this work, we developed a parametrized coarse-grained model of a chiral homopolymer and extensively characterized the resulting conformations. Specifically, the energetic parameter in the angular and dihedral potentials, the angular set point, and the dihedral set point are systematically varied to produce a wide range of conformations from a random coil to a nearly ideal helix. The average helicity, pitch, persistence length, and end-to-end distance are measured, and correlations between the model parameters and resulting conformations are obtained. Using available experimental data on model polypeptoid-based chiral polymers, we back out the required parameters that produce similar pitch and persistence length ratios reported in the experiments. The conformations for the experimentally matched chains appear to be somewhat flexible, exhibiting some helical turns. Our model is versatile and can be used to perform molecular dynamics simulations of chiral block copolymers and even sequence-specific polypeptides to study their self-assembly and to gain thermodynamic insights.

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Cross‐domain Chirality Transfer in Self‐Assembly of Chiral Block Copolymers

Yuan,

Chiu,

Liu

et al. 2024

Angewandte Chemie

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Chirality transfer is essential to acquire helical hierarchical superstructures from the self‐assembly of supramolecular materials. By taking advantage of chirality transfers at different length scales through intra‐chain and inter‐chain chiral interactions, helical phase (H*) can be formed from the self‐assembly of chiral block copolymers (BCPs*). In this study, chiral triblock terpolymers, polystyrene‐b‐poly(ethylene oxide)‐b‐poly(L‐lactide) (PS‐PEO‐PLLA), and polystyrene‐b‐poly(4‐vinylpyridine)‐b‐poly(L‐lactide) (PS‐P4VP‐PLLA) are synthesized for self‐assembly. For PS‐PEO‐PLLA with an achiral PEO mid‐block that is compatible with PLLA (chiral end‐block), H* can be formed while the block length is below a critical value. By contrast, for the one with achiral P4VP mid‐block that is incompatible with PLLA, the formation of H* phase would be suppressed regardless of the length of the mid‐block, giving cylinder phase. Those results elucidate a new type of chirality transfer across the phase domain that is referred as cross‐domain chirality transfer, providing complementary understanding of the chirality transfer at the interface of phase‐separated domains.

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Self-Assembly of Semiflexible-Coil Chiral Block Copolymers under Various Segregation Strengths with Multiple Secondary Interactions

Cited by 11 publications

References 42 publications

Curving and Twisting in Self-Assembly of Triblock Terpolymers Driven by a Chiral End Block

Curving and Twisting in Self-Assembly of Triblock Terpolymers Driven by a Chiral End Block

A Tunable, Particle-Based Model for the Diverse Conformations Exhibited by Chiral Homopolymers

Cross‐domain Chirality Transfer in Self‐Assembly of Chiral Block Copolymers

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