Dense and strong, but superinsulating silica aerogel

Abstract Silica aerogel is the ultimate thermal insulator thanks to its record-breaking low conductivity (?), open porosity and hydrophobicity. aerogel's lowest at intermediate densities (? ? 0.11 g/cm3) and, because of strong, power-law dependence E modulus on density, this rather density so far led moduli. Even with polymer reinforcement, increasing stiffness only possible higher thus conductivity. This paper explores synthesis silica granules using ambient pressure drying provide enhanced mechanical whilst maintaining conductivities well below 20 mW m?1 K?1. The aging conditions affect interplay between properties, are varied optimize physical properties. dense (??0.29 g/cm3), but superinsulating (??15 K?1) aerogels presented in challenge community's understanding heat transport aerogels, do not rely reinforcement. underlying microscopic structural parameters affecting properties investigated by modelling simulation back-bone. Short times reduce cross-section of, through, inter-particle necks, leading an overall decrease through solid skeleton (?s). In addition, short-aged gels undergo a partial pore collapse during fluid due less aged, hence weaker network structures. resulting denser structure contains additional point contacts that increase stiffness, up order magnitude. However, these newly formed point-contacts limited gas phase conduction (?s) further suppressed even smaller sizes. Strong particles ideal fillers for composites, concrete renders. optimized APD available as granules, finally compiled composite insulation board effective down K?1 improved strength: 2-fold E, compared produced from classical granulate. possibility improve pure can help break into new high-strength, applications needed carbon emissions built environment.