New hybrid alginate-silica aerogel films

Silica aerogels already show good thermal insulation performance, but they are usually brittle, which particularly with thin films leads to poor handling. Various combinations of a silica aerogel phase and a strengthening biopolymer phase have been reported in the literature, but these are difficult to scale up.[1, 2] In this work, highly scalable processes were developed for the fabrication of mechanically stable hybrid silica-aerogel films. The particle composite material consisting of silica aerogel granules embedded in an alginate aerogel matrix enables bending radii of 10 mm. Scanning electron microscopy studies show that the superhydrophobic silica phase connects perfectly with the fibrillar alginate aerogel phase, see Figure 1. Films of a thickness of 750 µm with a volume ratio of silica aerogel to alginate aerogel of 1:1 were produced. The composite material is perfectly scalable from laboratory to large-scale production with manufacturing methods already established in the market. Due to the low average pore size of 14nm, which is mainly dominated by the silica phase, the measured thermal conductivity at 0°C is 0.018 W·(m·K)-1 and increases to 0.023 W·(m·K)-1 at 80°C. In the presentation, we will look at the manufacturing process and discuss the properties of the composite material based on applications