Abstract

Space cooling and lighting together consume 25% of global electricity, yet existing daytime radiative coolers are mostly limited to porous planar coatings that block visible light and lack durability. Here, we introduce rheology-optics coupling as a design principle that links polymer viscoelasticity to particle dispersion and optical scattering. Guided by this principle, we develop printable polydimethylsiloxane-zirconium oxide composites that achieve solar reflectance ( ~ 97.3%) and mid-infrared emissivity ( ~ 96.9%) comparable to the best reported values, despite a low filler loading of only ~4.5 vol.%. These scalable coatings provide up to 7.4 oC sub-ambient cooling and cut electricity use by 37% versus commercial paint in pilot-scale testing, while withstanding mechanical, thermal, and environmental stresses. Beyond planar coatings, the rheology-tunable polydimethylsiloxane-zirconium oxide ink enables direct ink writing of daylight-regulating architectures that deliver sub-ambient radiative cooling while admitting diffuse daylight for illumination, reducing both cooling and lighting demand. This work provides a practical and versatile platform for radiative cooling.

Data availability

The data supporting the findings of this study are available within the paper and its supplementary information files. Source data for all plots and graphs are provided with the paper. Source data are provided with this paper.

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Acknowledgements

L.C. acknowledges funding support from the Office of Naval Research under award number N000142412050 and the startup funds of University of Illinois. Imaging, optical spectra, rheology, and water contact angle measurements were carried out in part in the Materials Research Laboratory Central Research Facilities, University of Illinois. K.Z. thanks Dr. Chen Wang and Dr. Jay Taylor for their valuable help and discussion on 3D printing.

Author information

Author notes

These authors contributed equally: Kai Zhou, Songtao Tang, Pranto Karua.

Authors and Affiliations

Department of Mechanical Science and Engineering, the Grainger College of Engineering, University of Illinois Urbana-Champaign, Urbana, IL, USA

Kai Zhou, Songtao Tang, Pranto Karua, Diya Patel, Paul V. Braun & Lili Cai 1.

Department of Materials Science and Engineering, the Grainger College of Engineering, University of Illinois Urbana-Champaign, Urbana, IL, USA

Fukang Wu & Paul V. Braun 1.

U.S. Army Corps of Engineers, Engineer Research and Development Center, Construction Engineering Research Laboratory, Champaign, IL, USA

Sungmin Hong, Gwendolyn M. Reeser & Donald M. Cropek 1.

Department of Chemistry, University of Illinois Urbana-Champaign, Urbana, IL, USA

Paul V. Braun 1.

Materials Research Laboratory, the Grainger College of Engineering, University of Illinois Urbana-Champaign, Urbana, IL, USA

Paul V. Braun & Lili Cai

Authors

1. Kai Zhou
2. Songtao Tang
3. Pranto Karua
4. Fukang Wu
5. Sungmin Hong
6. Diya Patel
7. Gwendolyn M. Reeser
8. Donald M. Cropek
9. Paul V. Braun
10. Lili Cai

Contributions

†These authors contributed equally to this work. L.C., K.Z., S.T., and P.B. conceived the idea. K.Z. carried out optical simulation and material characterization experiments. K.Z., P.K., and S.T. performed DIW fabrication. K.Z., D.P., and P.K. conducted outdoor thermal measurements. S.T. performed LumiCool design, calculation, and experiments. F.W. assisted in micro-CT characterizations. P.K., S.H., G.M.R., and D.M.C. performed the field power consumption tests on sheds. L.C. supervised the project. L.C., S.T., K.Z. wrote the manuscript. All authors reviewed and commented on the paper.

Corresponding author

Correspondence to Lili Cai.

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Competing interests

L.C. is a co-founder of SolarMantle Inc. and an inventor on patents related to radiative cooling technologies. The remaining authors declare no competing interests.

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Zhou, K., Tang, S., Karua, P. et al. Printable polymer nanocomposites for scalable and architected radiative cooling. Nat Commun (2025). https://doi.org/10.1038/s41467-025-67831-0

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Received: 02 March 2025

Accepted: 09 December 2025

Published: 27 December 2025

DOI: https://doi.org/10.1038/s41467-025-67831-0