Multi-network PVA/SA aerogel fiber: Unveiling superior mechanical, thermal insulation, and extreme condition stability

Abstract

Aerogels are highly sought-after in thermal insulation textiles due to their exceptional porosity and low density. However, Current research on aerogels mainly centers on their fixed two- and three-dimensional structures, lacking design flexibility, which significantly restricts their practicality. In contrast, one-dimensional aerogel fibers, while offering design flexibility, face complex fabrication, challenges in continuous molding, and pore collapse issues. In this study, utilizing polyvinyl alcohol (PVA) and sodium alginate (SA) as raw materials, a cost-effective wet spinning, freeze-thaw cycling, and freeze-drying technique were employed to continuously produce multi-functional PVA/SA aerogel fibers with a stable network pore structure through the design of a multi-crosslinked interlocking network structure. The optimal preparation process for the aerogel fibers was explored and characterized. The resulting aerogel fibers exhibited a stable hierarchical pore structure at the microscale, featuring large pores, nested mesopores, and micropores. These fibers possessed a high specific surface area (115.88 m²/g), high porosity (92.42 %), low density (0.0632 g/cm³), low thermal conductivity (0.0378 W/(m·K)), and flame resistance (LOI: 26.8 %). Furthermore, their stable internal network scaffold structure endowed them with outstanding mechanical properties (3.6 cN/tex) and stability in extreme environments. These composite aerogel fibers offer great potential for high-performance thermal insulation textiles and products.