Biopolymer and Cellulose-Based Aerogels: The Next-Generation Porous Materials for Sustainable Applications

ABSTRACT: Recent advances in nanostructured biopolymers have positioned cellulose-based aerogels as potential alternatives in the next generation of lightweight porous materials, given their ultralow density, hierarchical porosity, and extremely high surface area. These materials provide a renewable platform for a range of applications such as advanced energy storage, water purification, energy efficient insulation, and biomedical scaffolds. Unlike traditional silica or polymeric aerogels, cellulose derived systems provide a unique combination of mechanical toughness and biodegradability. These systems provide an environmentally safe approach to high-performance architectures. This research critically reviews the design and manufacturing techniques of biopolymer aerogels, including the choice of precursors, sol-gel chemistry, and drying techniques such as freeze-drying and supercritical CO₂ extraction that control the structural stability and tunability. Special attention is beneficial to the programmable surface chemistry of cellulose nanofibrils and nanocrystals, which allows for precise control over pore shape, wettability, and hybrid assembly with nanoparticles or bioactive substances. Functionalization, particularly cross-linking, ionic interactions, and the inclusion of conductive fillers, is identified as an important control for improving performance under demanding conditions. Furthermore, life-cycle assessments show that their carbon footprint and embodied energy are much lower than those of their fossil-based counterparts. In the context of the circular economy, cellulose-based aerogels still need to overcome challenges related to cost competitiveness, moisture sensitivity, and large-scale manufacturability. Hybrid architectures and processes that are industrially viable are needed to realise their full potential.