Humidity-Dependent Thermal Boundary Conductance Controls Heat Transport of Super-Insulating Nanofibrillar Foams
Varvara Apostolopoulou‐Kalkavoura, Shiqian Hu, Nathalie Lavoine, Mohit Garg, Mathieu Linares, Pierre Munier, Igor Zozoulenko, Junichiro Shiomi, Lennart Bergström
Abstract
We show that anisotropic foams based on aligned cellulose nanofibrils are superinsulating also at high relative humidity (RH). Thermal conductivity measurements and non-equilibrium molecular dynamic simulations show that the moistureinduced swelling and increase of the inter-fibrillar distance results in a reduction of the thermal boundary conductance that exceeds the thermal conductivity increase due to water uptake up to 75% RH. Phonon engineering by moisture could be used to tailor the heat transfer properties of hygroscopic nanofibrillar materials.
Topics & Concepts
Materials scienceThermal conductivityMoistureComposite materialRelative humidityHumidityThermalCelluloseNanocelluloseChemical engineeringThermodynamicsPhysicsEngineeringAdvanced Cellulose Research StudiesAerogels and thermal insulationElectromagnetic wave absorption materials