Catalyst-Free Dynamic Networks for Recyclable, Self-Healing Solid Polymer Electrolytes

Journal of the American Chemical Society, Год журнала: 2019, Номер 141(48), С. 18932 - 18937

Опубликована: Ноя. 19, 2019

Polymer networks with dynamic covalent cross-links act as solids but can flow at high temperatures. They have been widely explored reprocessable and self-healing materials, their use solid electrolytes is limited. Here we report poly(ethylene oxide)-based varying amounts of lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) to understand the impact a salt on ion transport network dynamics. We observed that conductivity our reached maximum 3.5 × 10–4 S/cm an optimal LiTFSI concentration. Rheological measurements showed amount significantly affects mechanical properties, shear modulus varies between 1 10 MPa stress relaxation by 2 orders magnitude. Additionally, found these efficiently dissolve back pure monomers heal recover after damage, showing potential sustainable electrolytes.

Язык: Английский

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Self-Healing Hydrogel with a Double Dynamic Network Comprising Imine and Borate Ester Linkages

Chemistry of Materials, Год журнала: 2019, Номер 31(15), С. 5576 - 5583

Опубликована: Июль 16, 2019

A self-healing hydrogel enriched with properties from a double-dynamic network (DDN) that has been prepared via two dynamic linkages (imine and borate ester) by using single polymeric cross-linker. The four-component Ugi reaction was used for easily synthesizing multifunctional poly(ethylene glycol) (MF-PEG) benzaldehyde group phenylboronic acid at each end of the chain. This MF-PEG simultaneously cross-linked poly(vinyl alcohol) through ester glycol chitosan an imine to generate unique DDN structure in seconds under mild conditions (pH ≈ 7, 25 °C). showed enhanced strength mucoadhesive abilities because complimentary interpenetrating networks. satisfying biocompatibility further vivo mouse model. injected successfully deliver antitumor drug achieved superior performance compared traditional delivery methods. To best our knowledge, this is first report prepare hydrogel. We hereby propose general strategy facile preparation materials improved properties. also opens new avenue multifunctional/reinforced combination chemistry multicomponent reactions.

Язык: Английский

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Neighboring Group Participation and Internal Catalysis Effects on Exchangeable Covalent Bonds: Application to the Thriving Field of Vitrimer Chemistry

Macromolecules, Год журнала: 2021, Номер 54(9), С. 3927 - 3961

Опубликована: Апрель 19, 2021

Vitrimers constitute a fascinating class of polymer materials that make the link between historically opposed 3D networks (thermosets) and linear polymers (thermoplastics). Their chemical resistance, reshaping ability, unique rheological behavior upon heating them promising for future applications in industry. However, many vitrimers require use high catalyst loadings, which raises concerns their durability limits potential applications. To cope with this issue, internal catalysis neighboring group participation (NGP) can be used to enhance ability such materials. A few studies report effect activating groups on exchange reactions vitrimers. Nevertheless, knowledge topic remains scarce, although research would greatly benefit from NGP already known organic chemistry. The present Perspective presents different types exchangeable bonds implemented discusses have or potentially capable an enhancing reactions. This analysis is underpinned by thorough mechanistic discussion various presented.

Язык: Английский

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Covalent Adaptable Networks Using β-Amino Esters as Thermally Reversible Building Blocks

Journal of the American Chemical Society, Год журнала: 2021, Номер 143(24), С. 9140 - 9150

Опубликована: Июнь 14, 2021

In this study, β-amino esters, prepared by the aza-Michael addition of an amine to acrylate moiety, are investigated as building blocks for formation dynamic covalent networks. While such amino esters usually considered thermally nondynamic adducts, kinetic model studies presented here show that exchange occurs via both reaction and catalyst-free transesterification. This knowledge is transferred create ester-based adaptable networks (CANs) with coexisting dissociative associative reactions. The ease, robustness, versatility chemistry demonstrated using a variety readily available multifunctional acrylates amines. CANs reprocessed either or transesterification in presence hydroxyl moieties. results reprocessable, densely cross-linked materials glass transition temperature (Tg) ranging from -60 90 °C. Moreover, even low Tg materials, high creep resistance was at elevated temperatures up 80 When additional β-hydroxyl group-containing applied during network design, enhanced neighboring group participation effect allows reprocessing 10 times 150 °C within 30 min while maintaining their material properties.

Язык: Английский

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Importance of Broad Temperature Windows and Multiple Rheological Approaches for Probing Viscoelasticity and Entropic Elasticity in Vitrimers

Macromolecules, Год журнала: 2021, Номер 54(10), С. 4782 - 4791

Опубликована: Май 5, 2021

Model polydimethylsiloxane telechelic vitrimers with dynamic boronic ester bonds were synthesized to investigate the viscoelastic properties of networks extremely low Tg via multiple rheological approaches. Frequency sweeps and stress relaxation tests, conducted at more than 120 °C above Tg, show anticipated Arrhenius behavior time inverse temperature give same activation energy for a fixed molecular weight, obtained using variety analysis methods. Time–temperature superposition demonstrates that flow regime is thermorheologically simple, while modulus plateau increases increasing temperature, consistent conserved network topology associative bond exchange. As times decrease, rubbery increases, indicating decoupling terminal dynamics from mechanics. Below 40 °C, second lower emerges, which attributed transition dominated by reaction exchange kinetics dictated local polymer dynamics. Our work points importance assessing broad window approaches in probing networks.

Язык: Английский

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