Advancing the Mechanosensitivity of Atropisomeric Diarylethene Mechanophores through a Lever-Arm Effect

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

Published: Jan. 10, 2025

Understanding structure–mechanical activity relationships (SMARs) in polymer mechanochemistry is essential for the rational design of mechanophores with desired properties, yet SMARs noncovalent mechanical transformations remain relatively underexplored. In this study, we designed a subset diarylethene based on lever-arm hypothesis and systematically investigated their toward noncovalent-yet-chemical conversion atropisomer stereochemistry. Results from Density functional theory (DFT) calculations, single-molecule force spectroscopy (SMFS) measurements, ultrasonication experiments collectively support confirm exceptional sensitivity chemo-mechanical coupling these atropisomers. Notably, transition M3 featuring extended 5-phenylbenzo[b]thiophene aryl groups determined to be 131 pN ± 4 by SMFS. This value lower than those typically recorded other mechanically induced chemical processes, highlighting its low-magnitude forces. work contributes fundamental understanding atropisomeric configurational paves way designing highly sensitive mechanochemical processes that could facilitate study nanoscale behaviors across scientific disciplines.

Language: Английский

Ultrasound Cavitation Enables Rapid, Initiator‐Free Fabrication of Tough Anti‐Freezing Hydrogels

Advanced Science, Journal Year: 2025, Volume and Issue: unknown

Published: April 17, 2025

Abstract Hydrogels are often synthesized with thermal or photo‐initiated gelation, leaving alternative energy sources less explored. While ultrasound has been used for polymer synthesis and mechanochemistry, its application through cavitation hydrogel as a constructive force is rare, the underlying sonochemical mechanisms poorly understood. Here, mechanism of rapid, initiator‐free, oxygen‐tolerant fabrication tough anti‐freezing hydrogels reported. By incorporating polyol solvents interpenetrating polymers into gelling solution, radical generation amplified network formation enhanced. Using polyacrylamide‐alginate model system, rapid gelation (as fast 2 minutes) high fracture toughness (up to 600 J m − ) demonstrated. varying intensity, crosslinker‐to‐monomer ratio, glycerol concentration, synthesis‐structure‐property relation established resulting sonogels uncovered using combined molecular, optical, mechanical testing techniques. The coupling convection under results in unique structural properties. Additionally, constructs demonstrated both non‐focused high‐intensity focused ultrasound. This work establishes foundation ultrasound‐driven sono‐fabrication highlights new avenues soft materials, advanced manufacturing, bioadhesives, tissue engineering.

Language: Английский

Constructing Strong and Tough Polymer Elastomers via Photoreversible Coumarin Dimer Mechanophores

ACS Applied Materials & Interfaces, Journal Year: 2024, Volume and Issue: 17(1), P. 2339 - 2348

Published: Dec. 26, 2024

Advanced elastomers with outstanding strength, toughness, and reusability hold significant potential for diverse applications. Using photochemistry mechanochemistry to develop such materials has become a very effective strategy. Here, we report that photoreversible coumarin-based mechanophores can make force-/light-triggered cycloreversion are chemically incorporated into polyurethane simultaneously enhance their strength toughness. Coumarin dimer mechanophore cross-linkers formed in the elastomer after exposure 365 nm irradiation, leading networks dramatically enhanced mechanical properties. The tensile of HNA-PU2000 coumarin could increase from 13.9 26.9 MPa, elongation at break 726 1053%, toughness 25.6 119.7 MJ·m–3, contrast its counterpart without mechanophores. Additionally, exhibits decent reusable capability via under stress or 254 irradiation. This mechano-/photochemical strategy improve provides facile approach development high-performance materials.

Language: Английский