Coil‐helix and sheet‐helix block copolymers via macroinitiation from telechelic <scp>ROMP</scp> polymers

Elacqua, Elizabeth; Croom, Anna; Lye, Diane S.; Weck, Marcus

doi:10.1002/pola.28542

Cited by 15 publications

(17 citation statements)

References 43 publications

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“…A rule set has been established for understanding how SCNPs can be designed for compactness and greater ordering, mainly through molecular dynamics simulations. Three ways in which these structures become more ordered is through intrachain homocoupling, intrachain heterocoupling, and cross-linking-induced collapse. ,, Similar to proteins, SCNPs require cross-linking in poor solvent conditions to achieve a high amount of compactness, as favorable solvent only induces local globule formation with substantial disorder. , In practice, the benefit of hydrophobicity to inducing order has been shown with various ABA triblock copolymers in which a hydrophobic core has enabled packed sphere formation. ,, Additionally, supramolecular chemistry via hydrogen bonding aids in creating stable ordered structures. − …”

Section: Introductionmentioning

confidence: 99%

“…7,13 In practice, the benefit of hydrophobicity to inducing order has been shown with various ABA triblock copolymers in which a hydrophobic core has enabled packed sphere formation. 18,20,21 Additionally, supramolecular chemistry via hydrogen bonding aids in creating stable ordered structures. 22−24 However, the major obstacles facing design of compact, ordered SCNPs are polydispersity and chain-to-chain compositional variations.…”

Section: ■ Introductionmentioning

confidence: 99%

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PET-RAFT and SAXS: High Throughput Tools To Study Compactness and Flexibility of Single-Chain Polymer Nanoparticles

et al. 2019

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From protein science, it is well understood that ordered folding and 3D structure mainly arise from balanced and noncovalent polar and nonpolar interactions, such as hydrogen bonding. Similarly, it is understood that single-chain polymer nanoparticles (SCNPs) will also compact and become more rigid with greater hydrophobicity and intrachain hydrogen bonding. Here, we couple high throughput photoinduced electron/energy transfer reversible addition–fragmentation chain-transfer (PET-RAFT) polymerization with high throughput small-angle X-ray scattering (SAXS) to characterize a large combinatorial library (>450) of several homopolymers, random heteropolymers, block copolymers, PEG-conjugated polymers, and other polymer-functionalized polymers. Coupling these two high throughput tools enables us to study the major influence(s) for compactness and flexibility in higher breadth than ever before possible. Not surprisingly, we found that many were either highly disordered in solution, in the case of a highly hydrophilic polymer, or insoluble if too hydrophobic. Remarkably, we also found a small group (9/457) of PEG-functionalized random heteropolymers and block copolymers that exhibited compactness and flexibility similar to that of bovine serum albumin (BSA) by dynamic light scattering (DLS), NMR, and SAXS. In general, we found that describing a rough association between compactness and flexibility parameters (R g/R h and Porod exponent, respectively) with log P, a quantity that describes hydrophobicity, helps to demonstrate and predict material parameters that lead to SCNPs with greater compactness, rigidity, and stability. Future implementation of this combinatorial and high throughput approach for characterizing SCNPs will allow for the creation of detailed design parameters for well-defined macromolecular chemistry.

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Section: Introductionmentioning

confidence: 99%

Section: ■ Introductionmentioning

confidence: 99%

PET-RAFT and SAXS: High Throughput Tools To Study Compactness and Flexibility of Single-Chain Polymer Nanoparticles

et al. 2019

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“…Our two helical blocks are based upon poly( N -1-(naphthalene-1-yl)ethyl)methacrylamide and poly(aryl isocyanide) (PIC). , We synthesize monotelechelic PMAc through RAFT polymerization in the presence of a functional chain-transfer agent (CTA), while telechelic PIC is prepared via anionic polymerization with an alkynyl-palladium-functionalized initiator. , PMAc helices present a relatively more dynamic backbone, wherein polymer tacticity and sterics dictate helicity, as opposed to static PIC helices that demonstrate a high inversion barrier and feature a rigid backbone. , Helical PMAc can be influenced by its environment, while the overall structure is dependent on intrinsic hydrogen bonding akin to common biomolecular helices. Both static and dynamic helical domains are prominent in Nature; thus, we envision that their combined incorporation into bio-inspired synthetic designs will engender investigations into the interplay of both helices, including how they assemble cooperatively.…”

Section: Methodsmentioning

confidence: 99%

“…53,54 We synthesize monotelechelic PMAc through RAFT polymerization in the presence of a functional chain-transfer agent (CTA), while telechelic PIC is prepared via anionic polymerization with an alkynyl-palladium-functionalized initiator. 4,21 PMAc helices present a relatively more dynamic backbone, wherein polymer tacticity and sterics dictate helicity, as opposed to static PIC helices that demonstrate a high inversion barrier and feature a rigid backbone. 55,56 Helical PMAc can be influenced by its environment, while the overall structure is dependent on intrinsic hydrogen bonding 51 akin to common biomolecular helices.…”

Section: ■ Research Designmentioning

confidence: 99%

“…To date, well-established routes to fabricate bio-inspired polymers are limited and rely mainly on single-chain polymer collapse, ,,, which, although elegant in approach, is limited in the complexity of polymer backbones that can be integrated within the target scaffold. In this contribution, we exploit the controlled polymerization of structurally simple yet complex monomers to engineer polymers containing secondary structures such as helices, sheets, or random coils , that are capable of further assembly into localized tertiary structures. Our strategy takes these elements and, through high-fidelity orthogonal molecular recognition processes, engineers three-dimensional (3D) architectures from well-defined secondary-structure-containing building blocks.…”

Section: Introductionmentioning

confidence: 99%

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Supramolecular Multiblock Copolymers Featuring Complex Secondary Structures

et al. 2017

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This contribution introduces main-chain supramolecular ABC and ABB'A block copolymers sustained by orthogonal metal coordination and hydrogen bonding between telechelic polymers that feature distinct secondary structure motifs. Controlled polymerization techniques in combination with supramolecular assembly are used to engineer heterotelechelic π-sheets that undergo high-fidelity association with both helical and coil-forming synthetic polymers. Our design features multiple advances to achieve our targeted structures, in particular, those emulating sheet-like structural aspects using poly(p-phenylenevinylene)s (PPVs). To engineer heterotelechelic PPVs in a sheet-like design, we engineer an iterative one-pot cross metathesis-ring-opening metathesis polymerization (CM-ROMP) strategy that affords functionalized Grubbs-II initiators that subsequently polymerize a paracyclophanediene. Supramolecular assembly of two heterotelechelic PPVs is used to realize a parallel π-sheet, wherein further orthogonal assembly with helical motifs is possible. We also construct an antiparallel π-sheet, wherein terminal PPV blocks are adjacent to a flexible coil-like poly(norbornene) (PNB). The PNB is designed, through supramolecular chain collapse, to expose benzene and perfluorobenzene motifs that promote a hairpin turn via charge-transfer-aided folding. We demonstrate that targeted helix-(π-sheet)-helix and helix-(π-sheet)-coil assemblies occur without compromising intrinsic helicity, while both parallel and antiparallel β-sheet-like structures are realized. Our main-chain orthogonal assembly approach allows the engineering of multiblock copolymer scaffolds featuring diverse secondary structures via the directional assembly of telechelic building blocks. The targeted assemblies, a mix of sequence-defined helix-sheet-coil and helix-sheet-helix architectures, are Nature-inspired synthetic mimics that expose α/β and α+β protein classes via de novo design and cooperative assembly strategies.

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Folded Well‐Defined 3D Architecture from Synthetic Helical and Sheet‐Like Polymers

Wang,

Mann,

Hannigan

et al. 2024

Adv Funct Materials

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The fabrication of truly hierarchically folded single‐chain polymeric nanoparticles with primary, secondary, and defined 3D architecture is still an unfulfilled goal. In this contribution, a polymer is reported that folds into a well‐defined 3D structure from a synthetic sheet‐helix block copolymer. The sheet‐like poly(p‐phenylene vinylene) (PPV) block is synthesized via the ring‐opening metathesis polymerization of a thymine‐bearing dialkoxy‐substituted [2.2]paracyclophane‐1,9‐diene. The PPV block is terminated with a Pd complex using a Pd‐containing chain‐terminating agent. The terminal Pd complex catalyzes the polymerization of isocyanide monomers with side‐chains containing either a chiral menthol or an achiral diaminopyridine resulting in the formation of a helical poly(isocyanide) (PIC) random copolymer. The PIC side‐chains are capable of engaging in complementary hydrogen‐bonding with thymine units along the PPV block resulting in the folding of the two secondary structural domains into a well‐defined 3D structure. The folding and unfolding of the polymer in both chloroform and THF are monitored using dynamic light scattering and NMR spectroscopy. This work is the first example of a hierarchically folded synthetic polymer featuring a defined 3D structure achieved by using two different polymer backbones with two distinct secondary structures.

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Coil‐helix and sheet‐helix block copolymers via macroinitiation from telechelic ROMP polymers

Cited by 15 publications

References 43 publications

PET-RAFT and SAXS: High Throughput Tools To Study Compactness and Flexibility of Single-Chain Polymer Nanoparticles

PET-RAFT and SAXS: High Throughput Tools To Study Compactness and Flexibility of Single-Chain Polymer Nanoparticles

Supramolecular Multiblock Copolymers Featuring Complex Secondary Structures

Folded Well‐Defined 3D Architecture from Synthetic Helical and Sheet‐Like Polymers

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