Preparation of nanocellulose aerogels by ice-templating: Structure regulation and performance study

In the context of energy shortages, low utilization rates, and resource scarcity, the demand for novel and high-efficiency energy-saving materials is increasing daily. As promising thermal insulation materials, pore structures significantly influence the performance of nanocellulose aerogels, rendering structural regulation an effective strategy for property enhancement. The fabrication of nanocellulose aerogels with tunable structures remains a significant challenge. In this study, nanocellulose aerogels were prepared from poplar wood-derived TEMPO-oxidized cellulose nanofibrils (TOCNFs) using an ice-templating technique. The morphological characteristics of the aerogels were regulated by manipulating the suspension concentration, freezing temperature, and temperature gradient. The relationship between microstructure and performance was systematically examined. Structural modulation conferred the aerogels with an ultralow thermal conductivity of 0.022 W/(m·K). These findings establish a foundation for the development of high-performance thermal insulation materials and offer a theoretical framework for the controlled fabrication and optimization of nanocellulose-based aerogels. • Development of a green, scalable strategy for fabricating bio-based aerogels with directional structure control. • In-depth analysis of structure–property relationships governing mechanical and thermal performance. • Demonstration of excellent thermal insulation, with enhanced environmental compatibility.