Structurally stable cellulose nanofiber-based phase change aerogels for thermal management and acoustic insulation

Abstract

Phase change materials (PCMs) hold great potential for thermal regulation in energy storage systems. However, their practical application is often hindered by challenges such as low thermal conductivity, leakage during phase transitions, and environmental concerns. This study introduces the creation of cellulose nanofiber-based phase change composite aerogels (CPCAs), which consist of cellulose nanofibers (CNFs), carbon nanotubes (CNTs), and polyethylene glycol (PEG) as the primary PCM. The aerogels were spray-coated with polylactic acid (PLA) to enhance their hydrophobicity (water contact angle over 100°), structural integrity, and sound absorption. The integration of CNTs markedly enhanced thermal conductivity (up to 0.516 W m⁻¹ K⁻¹) and compressive strength (903.7 kPa at 70% strain). In contrast, the highly porous CNF network facilitated effective PEG encapsulation (∼93%) and a substantial latent heat storage capacity (melting enthalpy ≈161.8 J g⁻¹). The CPCAs had exceptional phase change stability, exhibiting minimal PEG leakage after 180 minutes at 70 °C, and maintained over 90% of their heat storage efficiency following 100 thermal cycles. CPCAs also exhibited significant broadband sound absorption, achieving a noise reduction coefficient (NRC) of around 0.45, surpassing commercial polyurethane foams. These structurally durable and moisture-resistant CPCAs with multifunctional capabilities provide a solution for thermal energy management and noise reduction for energy-efficient building environments.