Construction of a multifunctional dual-network chitosan composite aerogel with enhanced tunability.

Typically, the tailorable versatility of biomass aerogels is attributed to the tunable internal molecular structure, providing broad application prospects. Herein, a simple and novel preparation strategy for developing multifunctional dual-network chitosan/itaconic acid (CSI) aerogel with tunability by using freeze-drying and vacuum heat treatment techniques. By regulating the temperature and duration of amidation reaction, electrostatic interactions between chitosan (CS) and itaconic acid (IA) was abstemiously converted into amide bond in frozen aerogel, with IA acting as an efficient in-situ cross-linking agent, which yielded CSI aerogels with different electrostatic/covalent cross-linking ratios. Heat treatment and tuning of the covalent cross-linking degree of CSI aerogel changed their microstructure and density, which led to enhanced performance. For example, the specific modulus of CSI1.5-160 °C-5 h (71.69 ± 2.55 MPa·cm3·g-1) increased by 119 % compared to that of CSI1.5 (32.73 ± 0.718 MPa·cm3·g-1), converting the material from superhydrophilic to hydrophobic (124° ± 3.6°), exhibiting favorable stability and heat transfer performance. In addition, part of -NH3+ of CS was retained in the electrostatic cross-linked network, endowing the aerogel with antibacterial properties. The findings of this study provide insights and a reliable strategy for fabricating biomass aerogel with good comprehensive performance via ingenious structural design and simple regulation methods.