A suspended system for measuring the thermal properties of membranes is presented. The sensitive thermal measurement is based on the 3ω dynamic method coupled to a Völklein geometry. The device obtained using micro-machining processes allows the measurement of the in-plane thermal conductivity of a membrane with a sensitivity of less than 10 nW/K (+∕-5 × 10(-3) Wm(-1) K(-1) at room temperature) and a very high resolution (ΔK/K = 10(-3)). A transducer (heater/thermometer) centered on the membrane is used to create an oscillation of the heat flux and to measure the temperature oscillation at the third harmonic using a Wheatstone bridge set-up. Power as low as 0.1 nW has been measured at room temperature. The method has been applied to measure thermal properties of low stress silicon nitride and polycrystalline diamond membranes with thickness ranging from 100 nm to 400 nm. The thermal conductivity measured on the polycrystalline diamond membrane support a significant grain size effect on the thermal transport.
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http://dx.doi.org/10.1063/1.4704086 | DOI Listing |
Soft Matter
January 2025
School of Chemistry and University of Sydney Nano Institute, The University of Sydney, Sydney, NSW, 2006, Australia.
Self-assembly of amphiphilic molecules can take place in extremely concentrated salt solutions, such as inorganic molten salt hydrates or hydrous melts. The intermolecular interactions governing the organization of amphiphilic molecules under such extreme conditions are not yet fully understood. In this study, we investigated the specific effects of ions on the self-assembly of the non-ionic surfactant CH(OCHCH)OH (CE) under extreme salt concentrations, using calcium nitrate tetrahydrate as a reference.
View Article and Find Full Text PDFMacromol Rapid Commun
January 2025
Laboratory of Material Chemistry for Energy Conversion and Storage, Ministry of Education, Hubei Key Laboratory of Material Chemistry and Service Failure, School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, Wuhan, 430074, China.
Janus graft copolymers, which combine the characteristics of block and graft copolymers, have been used in the fields of reaction catalysis, surface modification, and drug delivery, but their applications in lithium batteries have rarely been reported. Herein, Janus graft copolymers with polyethylene glycol (PEG) and polystyrene (PS) side chains are synthesized by combining reversible addition-fragmentation chain transfer (RAFT) polymerization and atom transfer radical polymerization (ATRP) methods and doped with lithium salts to fabricate Janus bottlebrush polymer electrolytes (PEG-J-PS). The PEG side chains of the brush polymers impart good ion-conducting properties to the electrolytes, while the PS side chains improve the mechanical strength and thermal and chemical stability of the electrolytes.
View Article and Find Full Text PDFNano Lett
January 2025
Institute of Electronics, National Yang Ming Chiao Tung University, Hsinchu 300093, Taiwan.
High-energy metal deposition significantly impacts the performance and reliability of two-dimensional (2D) semiconductors and nanodevices. This study investigates the localized annealing effect in atomically thin InO induced during high-energy metal deposition. The localized heating effect alters the electronic performance of InO devices, especially in shorter channel devices, where heat dissipation is further constrained.
View Article and Find Full Text PDFAdv Sci (Weinh)
January 2025
Department of Materials Science and Engineering, University of Maryland, College Park, MD, 20742, USA.
The optical modulation of ferroelectric polarization constitutes a transformative, non-contact strategy for the precise manipulation of ferroelectric properties, heralding advancements in optically stimulated ferroelectric devices. Despite its potential, progress in this domain is constrained by material limitations and the intricate nature of the underlying mechanisms. Recent studies have achieved efficient regulation of ferroelectric polarization and thermal conductivity in chiral ferroelectric thin films through the application of left- and right-handed circularly polarized light (LCP and RCP).
View Article and Find Full Text PDFACS Appl Mater Interfaces
January 2025
School of Mechanics and Aerospace Engineering, Dalian University of Technology, Dalian 116024, P. R. China.
Ceramic aerogels are promising high-temperature thermal insulation materials due to their outstanding thermal stability and oxidation resistance. However, restricted by nanoparticle-assembled network structures, conventional ceramic aerogels commonly suffer from inherent brittleness, volume shrinkage, and structural collapse at high temperatures. Here, to overcome such obstacles, 3D ultralight and highly porous carbon tube foams (CTFs) were designed and synthesized as the carbonaceous precursors, where melamine foams were used as the sacrificial templates to form the hollow and thin-wall network structures in the CTFs (density: ∼4.
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