Cooling aerogel inspired by white beetles combines cellulose, MOF-assisted pores, strong solar reflectance, and infrared emission to reduce building cooling demand while supporting biodegradable, low-carbon envelope applications for scalable construction.
Study: Natural-inspired sustainable cellulose cooling aerogel with hetero-photonic scattering network via hydration of metal-organic frameworks-induced interface assembly for energy-saving buildings. Image Credit: Gergitek/Shutterstock
A recent study in the Journal of Bioresources and Bioproducts presents a bioinspired passive radiative cooling aerogel developed for sustainable building applications. The research introduces a cellulose-based material inspired by the microscopic optical structure of white beetles to create a highly efficient hierarchical light-scattering network. The study demonstrates that the aerogel can achieve strong solar reflection and infrared thermal emission while maintaining environmental sustainability through its biodegradable cellulose-based design.
Nature-Inspired Design for Passive Building Cooling
Passive daytime radiative cooling has emerged as an important energy-efficient strategy for reducing building cooling demand without relying on electricity-intensive air-conditioning systems. These materials operate by reflecting incoming solar radiation while simultaneously dissipating thermal energy through the atmospheric infrared transparency window.
This process allows surfaces to remain cooler than the surrounding environment under direct sunlight. Growing interest in sustainable cooling technologies has increased research into materials capable of delivering high cooling performance while minimizing environmental impact.
Many existing radiative cooling materials face important performance and sustainability limitations. Conventional polymer-based systems often exhibit a trade-off between ultrahigh solar reflectance and strong infrared emissivity. Several aerogel-based coolers have relatively simple pore structures that limit their photon-scattering efficiency. In addition, many previously reported fabrication methods rely on complex processing techniques or petroleum-derived materials, which limit scalability and raise environmental concerns.
Researchers addressed these limitations by developing a bioinspired cellulose aerogel with a hierarchical microstructure modeled after the optical architecture of white beetles adapted to extremely hot environments. The engineered material incorporated interconnected pores, nanoparticles, and nanofibers that collectively enhanced broadband solar reflection and infrared thermal emission.
Engineering a Hierarchical Cooling Aerogel
The researchers developed the bioinspired cooling aerogel using nanofibrillated cellulose (NFC) and cellulose nanocrystals (CNC) as the primary structural materials. These renewable cellulose components formed the interconnected framework of the aerogel network. The team synthesized a hygroscopic metal-organic framework (MOF-801), which strongly influenced pore formation and hierarchical self-assembly.
The fabrication process began with the preparation of stable cellulose suspensions containing nanofibers and nanocrystals. Researchers introduced methyltrimethoxysilane (MTMS) to strengthen crosslinking within the network and improve structural stability. They then incorporated different concentrations of MOF-801 into the mixtures to investigate how hygroscopic particle content affected pore architecture, optical behavior, and cooling performance.
The aerogels were fabricated through directional freeze-casting followed by freeze-drying. During freezing, MOF-801 particles absorbed surrounding water molecules and altered local ice nucleation dynamics. The researchers characterized the resulting aerogels using multiple structural and chemical analysis techniques.
Scanning electron microscopy (SEM) revealed pore morphology and particle distribution, while X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), and X-ray photoelectron spectroscopy (XPS) examined structural bonding and intermolecular interactions.
The study also incorporated advanced computational simulations to evaluate optical and molecular behavior. Finite-difference time-domain modeling quantified light-scattering efficiency across different pore geometries and structural configurations. Density functional theory calculations further examined molecular interactions among cellulose, water molecules, and MOF particles during hierarchical self-assembly.
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To assess large-scale practical performance, the researchers conducted building energy simulations using EnergyPlus software across multiple climate regions in China. The team also performed life-cycle assessment analysis to evaluate environmental impact relative to petroleum-based insulation materials such as polystyrene foam and carbon-fiber-reinforced plastics.
Strong Optical Performance and Significant Energy Savings
The bioinspired cooling aerogel demonstrated significant improvement in optical and thermal performance compared with conventional cellulose aerogels. The optimized MCA 25 sample (25 mg of MOF-801) achieved a solar reflectance of 95.8% and an infrared emissivity of 95%. This combination enabled efficient solar reflection and heat dissipation through the atmospheric infrared window.
Microscopic characterization revealed that the hierarchical porous architecture played a critical role in enhancing broadband sunlight scattering. The multiscale structures generated numerous refractive-index interfaces that scattered sunlight over a broad wavelength range and improved overall reflectivity.
The researchers also found that MOF concentration strongly influenced structural organization and optical behavior. The MCA 25 composition provided the best balance between hierarchical pore formation, structural integrity, and cooling performance.
Thermal experiments further demonstrated the aerogel’s strong cooling capability under both laboratory and outdoor conditions. Under simulated solar illumination, the MCA 25 sample maintained significantly lower surface temperatures than conventional nanocellulose aerogels.
Outdoor testing conducted at Nanjing Forestry University demonstrated daytime sub-ambient cooling of 4.2 °C at 54% relative humidity and up to 7.1 °C at lower humidity levels. The researchers attributed this performance to strong sunlight scattering and efficient infrared thermal emission enabled by the hierarchical pore network and MOF nanoparticles.
Building simulations demonstrated average annual cooling energy savings of approximately 43.5% across China, with some hot regions exceeding 1,200–1,500 kWh annually. The aerogel also maintained high reflectance after UV exposure and biodegraded naturally within 21 days.
Conclusion and Future Potential for Sustainable Buildings
The study shows that bioinspired material design can significantly improve passive daytime radiative cooling performance while supporting sustainable building technologies. The developed cellulose-MOF aerogel serves as an environmentally friendly cooling material with a lightweight hierarchical structure. It combines strong solar reflection, efficient infrared heat emission, and low environmental impact within a single material platform. The material also demonstrated substantial cooling energy savings, highlighting its potential for building envelopes and roof-coating applications.
The study demonstrated how multiscale pore structures, hydrogen bonding, and MOF-assisted self-assembly collectively enhanced light-scattering and thermal-radiation efficiency. Although additional research is still needed to evaluate long-term outdoor durability and large-scale manufacturing feasibility, the findings provide a promising pathway for scalable passive cooling technologies. The study highlights the potential of biodegradable and low-carbon materials for future energy-efficient building applications.
Journal Reference
Yao, Q., Dong, G., et al. (2026). Natural-inspired sustainable cellulose cooling aerogel with hetero-photonic scattering network via hydration of metal-organic frameworks-induced interface assembly for energy-saving buildings. Journal of Bioresources and Bioproducts, 100267. DOI: 10.1016/J.JOBAB.2026.100267, https://www.sciencedirect.com/science/article/pii/S2369969826000393
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