Role of morphological arrangements in cellulose nanofiber-based aerogels for thermal insulation: A systematic review
Shakshi Bhardwaj, Shiva Singh, Pragya Gupta, Nitesh Choudhary, Pradip K. Maji
Abstract
Aerogels are highly porous solid-state structures with low density and have numerous properties, such as high absorption activity, low dielectric constant, high sound absorption, and low thermal conductivity. These properties made aerogels worthwhile as acoustic and thermal insulators, pharmaceutical carriers, flexible energy storage devices, and a template for synthesizing inorganic nanomaterials. From an environmental aspect, biodegradable and green aerogels are in light of the research. Cellulose, extracted from various natural sources, is the most abundant and environmentally benign material employed as a starting material for aerogels. This review provides insights into the introduction of cellulose nanofiber aerogels and their fabrication processes using various pre-treatment techniques, such as enzymatic, chemical, or ionic-liquid methods, and several drying methods. Following this, the properties, thermal performance, and morphology that affects the thermal insulation of nano-fibrillated cellulosic aerogels are discussed. Owing to their outstanding thermal insulating properties, nano-fibrillated cellulose aerogels would be a potential choice for insulation in building applications. The steps toward sustainability require such resource-bounded research development.