Synchronous Radiative Cooling and Thermal Insulation in SiO₂/Poly(vinyl alcohol) Composite Aerogel for Energy Savings in Building Thermal Management

ACS Sustainable Chemistry & Engineering, Journal Year: 2024, Volume and Issue: 12(14), P. 5695 - 5704

Published: March 27, 2024

Daytime passive radiative cooling is an effective way to reduce energy consumption for building cooling. However, overcooling might occur in at low-temperature which presents limitations thermal management. Herein, a new SiO2/poly(vinyl alcohol) composite aerogel with nanomicro–multistage porous structure insulation and was fabricated by non-solvent-assisted freeze-drying strategy. In the fabrication process, nonsolvent (acetone) poly(vinyl utilized control proportion size of macro-porous inside aerogel, making conductivity decreased 0.0390 W/mK while spontaneously increasing its solar reflectance infrared (8–13 μm) emissivity 93.70% 98.19%, respectively. The achieved sub-ambient up 14.1 °C during day above-ambient warming 3.8 night, avoiding nighttime overcooling. demonstrates adaptive management compared commercial materials, it suitable intelligent energy-saving buildings.

Language: Английский

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Fire‐Safe Aerogels and Foams for Thermal Insulation: From Materials to Properties

Advanced Materials, Journal Year: 2024, Volume and Issue: unknown

Published: Nov. 19, 2024

The ambition of human beings to create a comfortable environment for work and life in sustainable way has triggered great need advanced thermal insulation materials past decades. Aerogels foams present prospects as insulators owing their low density, good insulation, mechanical robustness, even high fire resistance. These merits make them suitable many real-world applications, such energy-saving building materials, thermally protective aircrafts battery, warming fabrics. Despite advances, date there remains lack comprehensive yet critical review on the materials. Herein, recent progresses fire-safe thermal-insulating aerogels are summarized, pros/cons three major categories aerogels/foams (inorganic, organic hybrids) discussed. Finally, key challenges associated with existing discussed some future opportunities proposed. This is expected expedite development insulating help sustainable, safe, energy-efficient society.

Language: Английский

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Building‐Envelope‐Inspired, Thermomechanically Robust All‐Fiber Ceramic Meta‐Aerogel for Temperature‐Controlled Dominant Infrared Camouflage

Advanced Materials, Journal Year: 2024, Volume and Issue: 36(25)

Published: March 16, 2024

The unsatisfactory properties of ceramic aerogels when subjected to thermal shock, such as strength degradation and structural collapse, render them unsuitable for use at large gradients or prolonged exposure extreme temperatures. Here, a building-envelope-inspired design fabricating thermomechanically robust all-fiber meta-aerogel with interlocked fibrous interfaces an interwoven cellular structure in the orthogonal directions is presented, which achieved through two-stage physical chemical process. Inspired by reinforced concrete building envelope, solid foundation composed frames constructed enhanced supramolecular situ self-assembly achieve high compressibility, retaining over 90% maximum stress under considerable compressive strain 50% 10 000 cycles, showing temperature-invariance compressed 60% within range -100 500 °C. As result its distinct response oscillation tolerance coupled elastic recovery, exhibits exceptional suitability shock resistance infrared camouflage performance cold (-196 °C) hot (1300 fields. This study provides opportunity developing effective management conditions.

Language: Английский

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Diatom-Inspired Nanoscale Heterogeneous Assembly Strategy for Constructing Thermal Insulating Wood-Based Aerogels with Exceptional Strength, Resilience, Degradability, and Flame Retardancy

ACS Nano, Journal Year: 2025, Volume and Issue: unknown

Published: Feb. 11, 2025

The potential of thermally insulated wood aerogels in energy-efficient engineering is constrained by their mechanical weakness and inadequate environmental stability. Combining minerals with offers promise for enhancing multifaceted performance. However, fabricating high-performance wood-based via organic–inorganic assembly remains challenging due to poor uniformity weak interfacial bonding. Herein, inspired diatoms, an ultrastrong flame-retardant biomimetic polymethylsilsesquioxane–wood aerogel (MSQW) fabricated combining a nanoscale heterogeneous strategy sol–gel process precisely engineer each level the hierarchy. Meanwhile, situ mineralization amorphous inorganic oligomers firmly welds interface, forming continuous homogeneous monolithic structure. resulting MSQW exhibits ultrahigh stiffness axial direction (Young's modulus 68.73 ± 3.20 MPa) withstands over 60% strain at 6.97 MPa radial direction, recovering its original shape after stress release, unique structural features. Additionally, excellent combination properties, including outstanding fire resistance ( peak heat release rate 91.13 kW/m2), hydrophobicity (water contact angle 137.3°), degradability. These advanced properties make ideal material thermal insulation harsh environments.

Language: Английский

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Acid‐Assisted Toughening Aramid Aerogel Monoliths with Ultralow Thermal Conductivity and Superior Tensile Toughness

Advanced Functional Materials, Journal Year: 2023, Volume and Issue: 34(2)

Published: Sept. 24, 2023

Abstract Resisting extreme loading and thermal ablation encountered by aerospace devices demands for high performance engineering materials. Aerogels have achieved satisfactory insulation but the intrinsic brittleness of porous skeletons fail to ensure their normal operation under severe stress fields. Herein, aramid nanofibers (ANFs) are processed into tough 3D aerogel monoliths via a multi‐scale toughening strategy, involving unidirectional freeze‐casting‐enabled microstructure orientation acid‐assisted nanofiber cross‐linking. Scalable production ANFs aerogels is realized through fast air‐drying without excessive energy consumption. The aligned sheets in enable conductivity 15.8 mW m −1 K , superinsulation from −130 300 °C, durable combustion protection 20 min. Particularly, highly aggregated assemble dense skeletons, endowing with superior specific tensile strength (89 MPa cm 3 g ), ultra‐high toughness (1.3 MJ −3 impressive fracture (7.36 kJ −2 ). Such mechanical properties resistant harsh environments, including water erosion (7 days) temperature baking (30 days). Moreover, exhibit two three times more dissipation than commercial foams against ballistic impact at 140 s . This integrated robustness may pioneer potential application impact‐thermal coupled safeguard

Language: Английский

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Multiphase Symbiotic Engineered Elastic Ceramic‐Carbon Aerogels with Advanced Thermal Protection in Extreme Oxidative Environments

Advanced Materials, Journal Year: 2024, Volume and Issue: 36(32)

Published: June 3, 2024

Abstract Elastic aerogels can dissipate aerodynamic forces and thermal stresses by reversible slipping or deforming to avoid sudden failure caused stress concentration, making them the most promising candidates for protection in aerospace applications. However, existing elastic face difficulties achieving reliable above 1500 °C aerobic environments due their poor thermomechanical stability significantly increased conductivity at elevated temperatures. Here, a multiphase sequence multiscale structural engineering strategy is proposed synthesize mullite‐carbon hybrid nanofibrous aerogels. The heterogeneous symbiotic effect between components simultaneously inhibits ceramic crystalline coarsening carbon etching, thus ensuring of nanofiber building blocks. Efficient load transfer high interfacial resistance crystalline‐amorphous phase boundaries on microscopic scale, coupled with mesoscale lamellar cellular locally closed‐pore structures, achieve rapid dissipation energy attenuation This robust material system compatible ultralight density (30 mg cm –3 ), compression strain 60%, extraordinary (up 1600 oxidative environments), ultralow (50.58 mW m –1 K 300 °C), offering new options possibilities cope harsh operating faced space exploration.

Language: Английский

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Biomimetic Leaf‐Vein Aerogel for Electromagnetic Wave Absorption and Thermal Superinsulation

Small, Journal Year: 2024, Volume and Issue: unknown

Published: June 7, 2024

Abstract Electromagnetic protection in extreme environments requires materials with excellent thermal insulation capability and mechanical property to withstand severe temperature fluctuations complex external stresses. Achieving strong electromagnetic wave absorption (EMA) while sustaining these exceptional properties remains a significant challenge. Herein, facile approach is demonstrated fabricate biomimetic leaf‐vein MXene/CNTs/PI (MCP) aerogel parallel venations through bidirectional freeze‐casting method. Due its multi‐arch lamellar structure within the layers, ultralight MCP (16.9 mg·cm −3 ) achieves minimum reflection loss (RL min of −75.8 dB maximum effective bandwidth (EAB max 7.14 GHz an absorber content only 2.4 wt%, which also exhibits superelasticity structural stability over wide range from −196 400 °C. Moreover, this unique facilitates rapid heat dissipation significantly impeding transfer between adjacent achieving ultralow conductivity 15.3 mW·m −1 ·K for superinsulation. The combination EMA performance, robust stability, superinsulation provides potential design scheme under conditions, especially aerospace applications.

Language: Английский

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Rapid Thermochromic and Highly Thermally Conductive Nanocomposite Based on Silicone Rubber for Temperature Visualization Thermal Management in Electronic Devices

ACS Applied Materials & Interfaces, Journal Year: 2024, Volume and Issue: 16(6), P. 7883 - 7893

Published: Feb. 1, 2024

Effective heat dissipation and real-time temperature monitoring are crucial for ensuring the long-term stable operation of modern, high-performance electronic products. This study proposes a silicon rubber polydimethylsiloxane (PDMS)-based nanocomposite with rapid thermal response high conductivity. enables both The reported material primarily consists thermally conductive layer (Al2O3/PDMS composites) reversible thermochromic (organic material, graphene oxide, PDMS nanocoating; OTM-GO/PDMS). conductivity OTM-GO/Al2O3/PDMS nanocomposites reached 4.14 W m–1 K–1, reflecting an increase 2200% relative to that pure PDMS. When operating 35, 45, 65 °C, surface turned green, yellow, red, respectively, time was only 30 s. also exhibited outstanding repeatability maintained excellent color stability over 20 repeated applications.

Language: Английский

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Direct Assembly of Aerogel Micro‐Nanofiber/MXene Sponges with Dual‐Network Structures for All‐Day Personal Heating

Advanced Functional Materials, Journal Year: 2024, Volume and Issue: 34(27)

Published: Feb. 21, 2024

Abstract Maintaining human body temperature under low is crucial to well‐being, thereby urgently requiring for high‐performance warmth retention materials. However, designing such materials with both mechanical robustness and warming up the complex changing outdoor environments remains challenging. Here, a dual‐network structured aerogel micro‐nanofiber/MXene sponge directly synthesized by synchronous occurrence of electrospinning electrospraying. Tailoring phase inversion solution jet creates micro‐nanofibers highly porous structures, which exhibit nanoscale aperture (30–60 nm) high single fiber surface aera (56.5 m 2 g −1 ). Under strong hydrogen bonding interaction, structures are constructed chemical entanglement between self‐assembled MXene networks, achieving robust stretchable compressible property. The nanopores cause Knudsen effect suppress slippage air molecules, enhancing unique capacity block heat energy. Further integrating passive radiative heating active performance as‐designed offers an all‐day personal system rise skin over 3.5 °C. This work may provide new candidates applications within aerospace, energy, transportation, building.

Language: Английский

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Renewable biomass-based aerogels: from structural design to functional regulation

Chemical Society Reviews, Journal Year: 2024, Volume and Issue: 53(14), P. 7489 - 7530

Published: Jan. 1, 2024

Global population growth and industrialization have exacerbated the nonrenewable energy crises environmental issues, thereby stimulating an enormous demand for producing environmentally friendly materials. Typically, biomass-based aerogels (BAs), which are mainly composed of biomass materials, show great application prospects in various fields because their exceptional properties such as biocompatibility, degradability, renewability. To improve performance BAs to meet usage requirements different scenarios, a large number innovative works past few decades emphasized importance micro-structural design regulating macroscopic functions. Inspired by ubiquitous random or regularly arranged structures materials nature ranging from micro meso macro scales, constructing microstructures often corresponds completely functions even with similar biomolecular compositions. This review focuses on preparation process, concepts, regulation methods, synergistic combination chemical compositions porous perspective gel skeleton pore structure. It not only comprehensively introduces effect physical BAs, but also analyzes potential applications corresponding thermal management, water treatment, atmospheric harvesting, CO

Language: Английский

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