Citation

Wicklein B, Kocjan A, Salazar-Alvarez G, Carosio F, Camino G, Antonietti M, Bergström L. Nat. Nanotechnol. 2014; 10(3): 277-283.

Affiliation

Department of Materials and Environmental Chemistry, Stockholm University, 106 91 Stockholm, Sweden.

Copyright

(Copyright © 2014, Holtzbrinck Springer Nature Publishing Group)

DOI

10.1038/nnano.2014.248

PMID

25362476

Abstract

High-performance thermally insulating materials from renewable resources are needed to improve the energy efficiency of buildings. Traditional fossil-fuel-derived insulation materials such as expanded polystyrene and polyurethane have thermal conductivities that are too high for retrofitting or for building new, surface-efficient passive houses. Tailored materials such as aerogels and vacuum insulating panels are fragile and susceptible to perforation. Here, we show that freeze-casting suspensions of cellulose nanofibres, graphene oxide and sepiolite nanorods produces super-insulating, fire-retardant and strong anisotropic foams that perform better than traditional polymer-based insulating materials. The foams are ultralight, show excellent combustion resistance and exhibit a thermal conductivity of 15 mW m(-1) K(-1), which is about half that of expanded polystyrene. At 30 °C and 85% relative humidity, the foams retained more than half of their initial strength. Our results show that nanoscale engineering is a promising strategy for producing foams with excellent properties using cellulose and other renewable nanosized fibrous materials.

Language: en