Discrete Block Copolymers: Precision Engineering on Multiple Length Scales

Macromolecules, Journal Year: 2025, Volume and Issue: unknown

Published: Feb. 26, 2025

Language: Английский

---

The future of sequence-defined polymers

European Polymer Journal, Journal Year: 2023, Volume and Issue: 199, P. 112465 - 112465

Published: Sept. 28, 2023

Language: Английский

---

Unveiling the Detailed Mechanism and Origins of Chemo-, Regio-, and Stereoselectivity of Rare-Earth Catalyzed Alternating Copolymerization of Polar and Nonpolar Olefins

Inorganic Chemistry, Journal Year: 2024, Volume and Issue: 63(7), P. 3544 - 3559

Published: Feb. 3, 2024

The direct copolymerization of polar and nonpolar olefins is great interest significance, as it the most atom-economical straightforward strategy for synthesis functional polyolefin materials. Despite considerable efforts, precise control monomer-sequence their regio- stereochemistry full challenges, related mechanistic origins are still in infancy to date. Herein, studies on model reaction Sc-catalyzed co-syndiospecific alternating anisylpropylene (AP) styrene were performed by DFT calculations. results suggest that subtle balance between electronic steric factors plays an important role during monomer insertions, a new amino-dissociated mechanism was proposed AP insertion at chain initiation. follows 2,1-si-insertion pattern, which mainly controlled caused restricted MeO···Sc interaction. As insertion, prefers 2,1-re-insertion manner its stereoselectivities influenced repulsions inserting polymer or ligand. More interestingly, found determined "steric matching" principle, quantitatively expressed buried volume metal center preinserted species. concept pocket has been successfully applied explain different performances several catalysts other reactions. insightful findings quantitative present here expected promote rational design rare-earth developing regio-, stereo-, sequence-controlled specific olefins.

Language: Английский

---

4D Printing of Physical Stimuli-Responsive Hydrogels for Localized Drug Delivery and Tissue Engineering

Polymer Reviews, Journal Year: 2024, Volume and Issue: unknown, P. 1 - 65

Published: Nov. 20, 2024

The biomedical industry has witnessed a transformative evolution with the advent of 3D printing technology. However, inherent limitations, such as inability to produce dynamic human tissues due absence temporal dimension, have persisted, resulting in static and inanimate printed products. To address this challenge enable creation living constructs, concept 4D emerged, marking paradigm shift additive manufacturing. In printing, time becomes fourth breathing life into previously creations. This review paper explores journey from pivotal role manufacturing process. Specifically, it highlights integration time-dependent responsive materials, focusing on stimuli-responsive hydrogels, cornerstone advancements. These materials exhibit remarkable ability adapt respond various stimuli, encompassing physical, chemical, biological signals. delves recent publications synergy between these stimuli shedding light their intricate interactions potential applications. One primary areas interest lies medical applications, notably tissue engineering, where holds immense promise. utilization creating biomimetic scaffolds that can dynamically complex environments. Furthermore, discusses technical considerations prospects technology, emphasizing its revolutionize landscape. amalgamation opens new avenues for personalized medicine, localized drug delivery, regenerative therapies, bridging gap requirements modern healthcare. present offers complete examination evolution, challenges, paving way innovations field.

Language: Английский

---

Mechanistic Insights into Rare-Earth-Catalyzed Alternating Copolymerization through C–H Polyaddition of Functionalized Organic Compounds to Unconjugated Dienes

Inorganic Chemistry, Journal Year: 2024, Volume and Issue: 63(18), P. 8079 - 8091

Published: April 25, 2024

Density functional theory (DFT) calculations have been conducted to elucidate the detailed mechanisms of yttrium-catalyzed C–H polyaddition 1,4-dimethoxybenzene (DMB) 1,4-divinylbenzene (DVB). It was computationally determined that DMB not only serves as a substrate but also performs crucial role ligand, stabilizing catalytically active species and promoting alkene insertion. Side pathways involving Cβ–H activation C═C continuous insertion were excluded due steric electronic factors, respectively, explaining why reaction occurred efficiently selectively give perfectly alternating DMB–DVB polymers. Interestingly, theoretical prediction reactivity N,N-dimethyl-1,4-phenylenediamine 2,2′-biethyl-4,4′-bipyridine reveals significant differences in coordination effects these substrates, leading distinct mechanisms, primarily influenced by their effects. These findings shed new light on previously overlooked ligand rare-earth-catalyzed step-growth copolymerization reactions.

Language: Английский

---

Revealing the Effect of Stereocontrol on Intermolecular Interactions between Abiotic, Sequence-Defined Polyurethanes and a Ligand

ACS Biomaterials Science & Engineering, Journal Year: 2024, Volume and Issue: 10(6), P. 3727 - 3738

Published: May 28, 2024

The development of precision polymer synthesis has facilitated access to a diverse library abiotic structures wherein chiral monomers are positioned at specific locations within macromolecular chains. These anticipated exhibit folding characteristics similar those biotic macromolecules and possess comparable functionalities. However, the extensive sequence space numerous variables make selecting with desired function challenging. Therefore, revealing sequence–function dependencies developing practical tools necessary analyze their conformations molecular interactions. In this study, we investigate effect stereochemistry, which dictates spatial location backbone pendant groups, on interaction between sequence-defined oligourethanes bisphenol A ligands. Various methods explored receptor-like properties model oligomers ligand. accuracy dynamics simulations experimental techniques is assessed uncover impact discrete changes in stereochemical arrangements resulting complexes binding strengths. Detailed computational investigations providing atomistic details show that formed demonstrate significant structural diversity depending stereocenters, thus affecting oligomer–ligand strength. Among tested techniques, fluorescence spectroscopy data, fitted Stern–Volmer equation, consistently aligned calculations, validating developed simulation methodology. methodology opens way engineer structure functionality explore applications, e.g., as sensory materials.

Language: Английский

---

Solid-Phase Synthesis of Well-Defined Multiblock Copolymers by Atom Transfer Radical Polymerization

Journal of the American Chemical Society, Journal Year: 2024, Volume and Issue: 146(32), P. 22247 - 22256

Published: July 30, 2024

Solid-phase polymer synthesis, historically rooted in peptide has evolved into a powerful method for achieving sequence-controlled macromolecules. This study explores solid-phase synthesis by covalently immobilizing growing chains onto poly(ethylene glycol) (PEG)-based resin, known as ChemMatrix (CM) resin. In contrast to traditional hydrophobic supports, CM resin's amphiphilic properties enable swelling both polar and nonpolar solvents, simplifying filtration, washing, drying processes. Combining atom transfer radical polymerization (ATRP) with techniques allowed the grafting of well-defined block copolymers high yields. approach is attractive successfully synthesizing di-, tri-, tetra-, penta-block excellent control over molecular weight dispersity. The also delves limitations weights due confinement within resin pores. Moreover, versatility demonstrated through its applicability various monomers organic aqueous media. straightforward offers rapid route developing tailored unique structures functionalities.

Language: Английский

---

Chain Shuttling Enantioselective Polymerization: An Effective Strategy for Synthesizing Stereoblock Polythioethers

Journal of the American Chemical Society, Journal Year: 2025, Volume and Issue: unknown

Published: Jan. 18, 2025

Herein, we propose to synthesize stereoblock polythioethers through the chain shuttling enantioselective ring-opening polymerization (ROP) of thiiranes. The use diastereoisomeric dinuclear Cr complexes with optimized steric hindrance allowed production both a head-to-tail content and isotacticity >99%. In particular, introduction dithiols enabled synthesis via process, thus producing sulfhydryl-telechelic tunable thermal properties. Experimental results density functional theory calculations indicate that configuration chiral axle complex determines enantioselectivity asymmetric ROP

Language: Английский

---

Programming mechanical properties through encoded network topologies

Journal of Polymer Science, Journal Year: 2024, Volume and Issue: 62(16), P. 3663 - 3680

Published: Jan. 12, 2024

Abstract Polymer networks remain an essential class of soft materials. Despite their use in everyday materials, connecting the molecular structure network to its macroscopic properties remains active area research. Much current research is enabled by advances modern polymer chemistry providing unprecedented level control over macromolecular structure. At same time, renewed interest self‐healing, dynamic, and/or adaptable materials continues drive substantial design. As part a special issue focused on performed Science and Engineering Department at University Massachusetts, Amherst, this review highlights connections between observed mechanical as investigated Tew group.

Language: Английский

---

Origins of Ligand-Controlled Stereoselective Polymerization of ortho-Methoxystyrene by Rare-Earth Catalysts: A Theoretical Perspective

Inorganic Chemistry, Journal Year: 2024, Volume and Issue: 63(20), P. 9195 - 9203

Published: May 9, 2024

The stereoselective polymerization of polar vinyl monomers has recently received much attention due to their excellent physicochemical properties. Over the past decade, breakthroughs have been achieved in this field by rare-earth catalysts. However, mechanistic origins those polymerizations still remain unclear. Herein, ortho-methoxystyrene (oMOS) several representative catalysts bearing different ligands (i.e., η5-C5Me5, pyridinyl-methylene-fluorenyl, quinolyl-anilido, β-diketiminato) were systematically investigated density functional theory (DFT) calculations. After achieving agreement between calculations and experiments, we focused on discussing role controlling stereoselectivity. Our results reveal that stereoregularity oMOS is mainly controlled steric effect catalyst–monomer structures. Specifically, type ligand influences orientation configuration inserting monomer, thereby affecting tacticity polymers. In cases η5-C5Me5-, quinolyl-anilido-ligated yttrium catalysts, observe consistent insertion directions alternating sides monomers, leading syndiotactic selectivity. opposite observed case β-diketiminato catalyst, isotactic These findings reported here offer valuable insights into stereoselectivity catalyzed coordination thus providing guidance for rational design new stereospecific future.

Language: Английский

---