Collaborative Research: Moisture-Dependent Thermal Transport in Cellulose-Derived Porous Materials

Michigan State University, East Lansing MI

Investigators

Abstract

High-performance thermal insulation is crucial for preventing heat loss and reducing energy bills in buildings and industrial sectors such as manufacturing, petroleum, and cryogenics. Conventional insulation materials, including glass wool, polystyrene foams, and many recycled cellulose products, degrade in thermal performance under humid conditions. In contrast, specifically designed porous insulators made from cellulose can behave differently, sometimes insulating even better with moisture. Unlike conventional materials, these advanced cellulose-based insulators can show complex thermal conductivity behavior, sometimes becoming better insulators with increasing humidity. This unique behavior happens because moisture can cause the structure of these advanced cellulose-based insulators to swell, which reduces heat conduction through the solid fiber network. While this offers the potential for enhanced insulation performance in humid environments, the underlying mechanisms governing these unconventional responses remain poorly understood, which limits practical applications. This project will close this important knowledge gap by studying how cellulose fiber dimensions, pore structures, and moisture collectively govern thermal transport in cellulose-based porous materials. This research will also create valuable learning opportunities by involving students at all levels in research, training, and curriculum development. The goal of this project is to understand how moisture affects heat flow in cellulose-based porous materials by linking molecular-level water-cellulose interactions to macroscopic thermal behavior. To achieve this, the research team integrates experimental and computational approaches across three specific aims: (1) establishing quantitative relationships for moisture-dependent thermal transport by fabricating a wide range of cellulose materials with controlled fiber sizes and pore structures and measuring their thermal conductivity under various humidity levels; (2) developing multiscale models that links molecular moisture interactions to macroscopic thermal transport; (3) using advanced characterization techniques, including neutron and X-ray scattering and spectroscopy, to observe how water partitions across multiscale pore structures and molecular domains and understand how this partitioning influences thermal pathways. This integrated approach will reveal the fundamental mechanisms driving moisture-dependent heat transfer, enabling the design of novel insulation with enhanced moisture resilience and advancing energy savings in buildings and industries while supporting economic opportunities through value-added biomass products. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.