ACS Macro Lett
Chemistry Department, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213, United States.
Published: March 2025
Brush particles, hybrid materials consisting of polymer chains tethered to particle surfaces, offer tunable properties that make them promising candidates for advanced functional materials. This study investigated the role of chain dispersity in the viscoelastic self-healing of poly (methyl acrylate) (PMA)-based brush particle solids. Increasing the molecular weight dispersity of grafted chains significantly enhanced both strain-to-fracture and toughness of brush particle solids, while the elastic modulus and glass transition temperature were independent of chain dispersity. Cut-and-adhere testing revealed a significant acceleration of the rate of toughness recovery in high-dispersity systems as compared to low-dispersity analogs for which toughness recovery markedly lagged the recovery of Young's modulus. The results suggest that structure and property recovery in brush particle solids are sensitive to the dynamical heterogeneity of brush canopies and highlight the role of molecular weight dispersity as a design parameter to enable hybrid materials with advanced self-healing ability.
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http://dx.doi.org/10.1021/acsmacrolett.5c00036 | DOI Listing |
ACS Macro Lett
March 2025
Chemistry Department, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213, United States.
Brush particles, hybrid materials consisting of polymer chains tethered to particle surfaces, offer tunable properties that make them promising candidates for advanced functional materials. This study investigated the role of chain dispersity in the viscoelastic self-healing of poly (methyl acrylate) (PMA)-based brush particle solids. Increasing the molecular weight dispersity of grafted chains significantly enhanced both strain-to-fracture and toughness of brush particle solids, while the elastic modulus and glass transition temperature were independent of chain dispersity.
View Article and Find Full Text PDFProc Natl Acad Sci U S A
March 2025
Department of Materials, ETH Zürich, Zürich 8093, Switzerland.
Contacts between particles in dense, sheared suspensions are believed to underpin much of their rheology. Roughness and adhesion are known to constrain the relative motion of particles, and thus globally affect the shear response, but an experimental description of how they microscopically influence the transmission of forces and relative displacements within contacts is lacking. Here, we show that an innovative colloidal-probe atomic force microscopy technique allows the simultaneous measurement of normal and tangential forces exchanged between tailored surfaces and microparticles while tracking their relative sliding and rolling, unlocking the direct measurement of coefficients of rolling friction, as well as of sliding friction.
View Article and Find Full Text PDFMacromol Rapid Commun
March 2025
Department of Chemistry, University of Prince Edward Island, 550 University Ave, Charlottetown, PE, C1A 4P3, Canada.
Surface fouling is a major concern in health care, marine industry, and water purification plants. Polymeric coatings are traditionally utilized to reduce the attachment of foulants on a surface, however low density and thickness of polymer brushes formed by surface initiated polymerization methods, surface exhaustion by continuous exposure to the foulants, and mechanical vulnerability in harsh environments, limit the antifouling performance of these traditional coatings. Recent trends in bioinspired polymeric coatings combine antifouling properties of super-hydrophobic, and highly hydrated lubricating polymers with mechanical properties of micro- and nano-particles to yield contact active, foulant releasable and stimuli responsive materials with superior antifouling performance.
View Article and Find Full Text PDFMacromol Rapid Commun
February 2025
Department of Chemistry, University of Tennessee, Knoxville, TN, 37996, USA.
Radioactive pertechnetate (TcO ) from the nuclear fuel cycle presents a severe risk to the environment due to its large solubility in water and non-complexing nature. By utilizing the chaotropic properties of TcO and its nonradioactive surrogate perrhenate (ReO ) and the principle of chaotropic interactions, a series of quaternary ammonium-containing polyelectrolyte brush-grafted silica particles are designed and applied to remove ReO from water. These cationic hairy particles (HPs) are synthesized by surface-initiated atom transfer radical polymerization of 2-(N,N-dimethylamino)ethyl methacrylate and subsequent quaternization with various halogen compounds.
View Article and Find Full Text PDFHeliyon
February 2025
Faculty of Mechanical Engineering, University of Prishtina "Hasan Prishtina", Prishtina, Kosovo.
Background: Marketed toothpastes vary in the extent to how much abrasive wear they cause to dentin. New abrasive particles in a dentifrice should be evaluated since there they can be at risk of abrasion to dentin and root surfaces.
Aim: The aim of this in vitro study was to evaluate abrasive dentin wear and surface roughness after brushing with whitening toothpaste containing zirconia at four different concentrations.
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