Mechanical and Tribological Performances Enhanced by Self‐Assembled Structures

Abstract

Taking inspiration from natural materials, composite materials can be reinforced by creating matrix architectures that can better accommodate and control internal stresses. Despite the recent success in the synthesis of artificial assemblies for local reinforcement through the introduction of oriented fibers and plates into host multilayered composites, there is a lack of fundamental understanding of the factors that determine mechanical properties. Moreover, designing building blocks and interfaces that facilitate higher resistance and energy dissipation is highly challenging. When the intrinsic material is fixed, the mechanical and tribological properties can be further adjusted. In this study, europium oxide nanosheets are arranged in interlocked‐junction superstructures that resist sliding at junction points, thereby enhancing the mechanical properties of the nanosheet assemblies compared to those of the conventional face‐to‐face superstructures formed by parallel nanosheets. Furthermore, the crystalline origin of building blocks is revealed by demonstrating that faulty crystal nanosheets adopting an amorphous structure are different from single‐crystal nanosheets, with the former exhibiting superior mechanical reinforcement and improved abrasive resistance.

Surfactant-Modified Silica Nanoparticles-Stabilized Magnetic Polydimethylsiloxane-in-Water Pickering Emulsions for Lubrication and Anticorrosion

“…Figure and Figures S11–S15, SI, show that a Al 2 O 3 disc treated with either the PDMS/water/CTACe or PDMS/water/SiO 2 @CTACe emulsion gave not only Ce 3d absorbance bands at around 886.0 and 906.0 eV that are correlated to the presence of Ce­(III) but also Ce 3d bands at ∼882.5 and ∼900.5 eV, corresponding to the appearance of CeO 2 . The results suggested that a portion of the [CeCl 3 Br] − ions should undergo tribochemical reactions to generate CeO 2 , which has been demonstrated to possess excellent lubricity. , The contribution of tribochemical reactions of [CeCl 3 Br] − to the tribological property can be supported by the much lower CoF values of both PDMS/water/CTACe and PDMS/water/SiO 2 @TTACe emulsions than that of PDMS oil, as well as a 3-fold enhanced CoF when using the PDMS/water/SiO 2 @CTABr emulsion at the same particle and surfactant concentrations (Figure A). The synergistic lubrication of silica nanospheres and CeO 2 tribochemical products eventually led to a prominently reduced interfacial friction and abrasion as illustrated in Figure .…”

Dual-Driven Mechanically and Tribologically Adaptive Hydrogels Solely Constituted of Graphene Oxide and Water

“…It resulted in stronger adhesion and transverse stretching, thus enhancing the structural stability of lamellar architecture. 26 This allowed more energy dissipation and load transfer between GO sheets thereafter optimizing the strength and antifriction of the hydrogel. 26 The low CoF suggests that pH 2 GOG was able to act as an effective lubricant, and this can be confirmed by a low wear volume and no presence of an apparent abrasive scar on the ZrO 2 /steel tribopair after its treatment (Figure 4).…”

“…26 This allowed more energy dissipation and load transfer between GO sheets thereafter optimizing the strength and antifriction of the hydrogel. 26 The low CoF suggests that pH 2 GOG was able to act as an effective lubricant, and this can be confirmed by a low wear volume and no presence of an apparent abrasive scar on the ZrO 2 /steel tribopair after its treatment (Figure 4). In comparison, dry GO, water, and GOGs at the other pH values all exhibited a much higher CoF and more severe surface abrasion (Figures 3 and 4, Figures S9−11).…”

“…Such behavior closely mimicked muscles and sea cucumbers, which can remarkably alter their mechanical strength and friction by topological reconfiguration of their internal microstructures, upon exposure to external stimuli or biological signals. ,,− The beneficial impact of layer-by-layer GO ordering on the mechanical and tribological performances is likely due to the weak association between the carboxyl groups favoring the fracture separations to occur in the edge-to-edge regions of GO sheets. It resulted in stronger adhesion and transverse stretching, thus enhancing the structural stability of lamellar architecture . This allowed more energy dissipation and load transfer between GO sheets thereafter optimizing the strength and antifriction of the hydrogel …”

“…It resulted in stronger adhesion and transverse stretching, thus enhancing the structural stability of lamellar architecture . This allowed more energy dissipation and load transfer between GO sheets thereafter optimizing the strength and antifriction of the hydrogel …”