Superstrong Alginate Aerogels

Abstract

Sodium alginate (SA) aerogels have received extensive attention in environmental modification, energy-related systems, and thermal insulation due to their good processability, nontoxicity, and biodegradability. However, achieving superior mechanical properties remains a significant challenge for SA aerogels as engineering materials. In this work, superstrong SA aerogels are prepared via an effective in situ crosslinking method, consisting of ice-templated preassembly followed by a specially designed dissolution process in mixing GDL/EtOH/H₂O (δ-glucolactone/ethanol/water) solution. Upon optimization of heat and mass transfer during the ice dissolution process, along with the unique ice template effect, a homogeneous, highly crosslinked, and long-range oriented structure in high-solid fraction SA matrices is obtained. The resultant SA aerogels (248.0 ± 4.4 mg cm⁻³) exhibit an outstanding specific modulus of 1.45 ± 0.15 GPa cm³ g⁻¹ (E = 360 ± 32 MPa, σ_y = 14.8 ± 0.8 MPa), remarkable energy absorption capability (32.1 ± 4.4 kJ kg⁻¹), and considerable thermal insulation performance (0.044 ± 0.007 W m⁻¹ K⁻¹). The present strategy paves a way for the fabrication of high-performance SA-based engineering materials with well-oriented microstructures and superior multifunctionality.