High-porosity hydrophobic (expand PVA)/(expand CNF) aerogels loaded with tetradecane for phase change cold storage
Zhijuan CHANG, Yanbo Pan, Yi Zhang, Xuehong Wu
Abstract
Conventional cold chain logistics reliant on mechanical refrigeration faces significant challenges, including high energy consumption and temperature fluctuations induced by equipment failure. To address these limitations, methyltrimethoxysilane (MTMS) was incorporated as a hydrophobic modifier into a polyvinyl alcohol (PVA)/cellulose nanofiber (CNF) composite system. A highly porous composite aerogel was subsequently fabricated via freeze-drying. This aerogel matrix served as a support for the vacuum impregnation of tetradecane, yielding a low-temperature composite phase change material (PCM) aerogel. The MTMS-modified PVA/CNF aerogel exhibits exceptional characteristics: a porosity of 96.80 % and a specific surface area of 54.10 m 2 /g, providing an optimal structural scaffold for high-capacity PCM encapsulation. Furthermore, the modified aerogel demonstrates hydrophobicity (water contact angle: 105.32°) and enhanced compressive strength, with a maximum stress of 1.23 MPa at 50 % strain, maintaining structural integrity under a 1.5 kg load. These properties collectively overcome the limitations of hydrophilic materials in high-humidity environments and mitigate PCM leakage. The resulting tetradecane-loaded composite PCM aerogel demonstrates excellent leakage resistance, with all samples showing leakage rates below 5 %. It also achieves a high phase change enthalpy of 297.8 J/g and exhibits minimal enthalpy loss (3.66 %) after 300 thermal cycles, indicating excellent cycling stability. An enhanced thermal conductivity of 0.383 W/(m·K) contributes significantly to improved thermal transfer efficiency. The combination of superior thermal performance and an appropriate phase transition temperature range (3–4 °C) positions this material as a promising candidate for food cold chain transportation. This study provides an effective strategy and new insights for utilizing phase change aerogels in cold chain logistics applications.