We explore the evolution of the mechanical properties of a coarsening foam containing colloidal particles that undergo a sol-gel transition in the continuous phase. This enables us to investigate the impact of elasto-capillarity on foam mechanics over a wide range of elasto-capillary numbers. Right after initiating aggregation the foam mechanics is predominantly determined by the elasticity of the bubbles, while the contributions of the continuous phase become dominant as the colloidal particles form a gel. Taking into account the confined configuration of the foam skeleton for the formation of a space spanning gel, we find that for elasto-capillary numbers exceeding unity the foam mechanics can be described as a simple linear combination of the contributions due to respectively the bubble elasticity and the elastic skeleton. Surprisingly, the contributions of the elastic skeleton to the overall foam mechanics are larger for smaller elasto-capillary numbers, scaling as the inverse of the capillary number.
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http://dx.doi.org/10.1039/c9sm02301a | DOI Listing |
RSC Adv
January 2025
Department of Chemistry, Carnegie Mellon University 4400 Fifth Avenue Pittsburgh PA 15213 USA
Polyurethanes (PU) make up a large portion of commodity plastics appearing in applications including insulation, footwear, and memory foam mattresses. Unfortunately, as thermoset polymers, polyurethanes lack a clear path for recycling and repurposing, creating a sustainability issue. Herein, using dynamic depolymerization, we demonstrate a simple one-pot synthesis for preparation of an upcycled polyurethane grafted graphene material (PU-GO).
View Article and Find Full Text PDFAngew Chem Int Ed Engl
January 2025
University of Thessaly, Mechanical Engineering, Leoforos Athinon, Pedion Areos, 383 34, Volos, GREECE.
To accelerate the water dissociation in the Volmer step and alleviate the destruction of bubbles to the physical structure of catalysts during the alkaline hydrogen evolution, an integrated electrode of cobalt oxide and cobalt-molybdenum oxide grown on Ni foam, named CoO-Co2Mo3O8, is designed. This integrated electrode enhances the catalyst-substrate interaction confirmed by a micro-indentation tester, and thus hinders the destruction of the physical structure of catalysts caused by bubbles. Electrochemical testing shows the occurrence of a surface reconstruction of the integrated electrode, and CoO is transformed into Co(OH)2, denoted as Co(OH)2-Co2Mo3O8.
View Article and Find Full Text PDFLangmuir
January 2025
School of Mechanical and Precision Instrument Engineering, Xi'an University of Technology, Xi'an 710048, China.
The interfacial mechanical characteristics of sandwich structures are crucial in defining the comprehensive mechanical performance of the whole structure. Nevertheless, in practical applications, the interface often emerges as the weakest segment due to potential defects in the interface of porous metal sandwich plates (PMSP). This study aims to explore the regulatory mechanisms influencing the mechanical characteristics of nano-SiO-reinforced aluminum foam sandwich structure (AFS) interfaces and to propose an effective strategy to achieve AFS interfaces with superior and stable mechanical properties.
View Article and Find Full Text PDFPolymers (Basel)
January 2025
Dipartimento di Chimica "G. Ciamician", Alma Mater Studiorum-Università di Bologna, Via F. Selmi 2, 40126 Bologna, Italy.
The development of greener substitutes for plastics is gaining massive importance in today's society. This also involves the medical field, where disposable materials are used to grant sterility. Here, a novel protocol using only a water-based solvent for the preparation of bio-based composite foams of actual β-chitin and collagen type I is presented.
View Article and Find Full Text PDFMaterials (Basel)
January 2025
Graduate School of Science and Technology, Gunma University, Kiryu 376-8515, Japan.
The porous structure, in which many pores are intentionally placed inside the material, has excellent impact energy absorption properties. Recent studies have attempted to fabricate multi-layered porous structures with different mechanical properties within a single porous structure sample, and the mechanical properties of these structures are being elucidated. However, these studies mainly attempted to vary the densities, pore structures, and alloy compositions within a single material, such as aluminum, for the entire sample.
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