Graphene‐Based Ultralight Compartmentalized Isotropic Foams with an Extremely Low Thermal Conductivity of 5.75 mW m⁻¹ K⁻¹

Abstract

The importance of high-performance thermal insulation materials is rapidly emerging due to energy conservation and the management of temperaturesensitive device perspectives. Recent thermal insulation materials including complex structures have been developed either by reducing the structural connectivity to mitigate thermal transport through solid conduction or forming directionally aligned confined inner pores to suppress the internal gas convection. In this study, to create a highly efficient thermal insulating material that suppresses thermal transport in all directions, graphene-based anisotropic closed-cellular structures (CCS) are devised with a highly ordered assembly of hollow compartments with extremely thin walls (≈50 nm). This uniquely designed CCS made from microfluidically synthesized graphene solid bubbles exhibited a remarkably low thermal conductivity of 5.75 mW m −1 K −1 thanks to effective suppression of both solid conduction and gas conduction/convection. Therefore, the proposed strategy in this work offers a novel toolkit for implementing next-generation high-performance insulation materials.

Crosslinking polydopamine/cellulose nanofibril composite aerogels by metal coordination bonds for significantly improved thermal stability, flame resistance, and thermal insulation properties

“…However, traditional silica aerogels are commonly characterized by fragility despite their good thermal and electrical properties, which significantly limits their application where mechanical robustness is needed. Therefore, many kinds of robust aerogels constructed from inorganic nanomaterials, such as silica nanofiber (Wang et al 2020a, b), carbon nanotube (Ozden et al 2017), graphene oxide (Oh et al 2021), or MXene (Deng et al 2019), and organic polymers, such as polyimide (Cashman et al 2020), polyamide (Williams et al 2014), poly(vinyl alcohol) (Ma et al 2017), or polyurethane (Donthula et al 2017), have been developed recently. However, these aerogels are more or less suffered from problems of cost, complicated processing, suspicious biocompatibility, environmental issues, and so on.…”

Microextrusion Foaming of Polyetheretherketone Fiber: Mechanical and Thermal Insulation Properties

“…[44,45] When the cell size of the polymer foam is reduced below micrometers, the Knudsen effect will cause a significant decrease in thermal conductivity. [46,47] In this work, the crucial factors that affect the thermal insulation properties of porous PEEK fibers with a microcellular structure are void fraction and thickness. Table 2 shows the void fraction (V f ) and diameter (d) of porous fibers with different drafting speeds (0À60 rpm).…”

Facile Method for Preparing Hierarchical Al2O3–Glass Foam Ceramics with Superior Thermal Insulating Property

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