Novel and simple design of nanostructured, super-insulative and flexible hybrid silica aerogel with a new...

This study reports a new strategy to fabricate a thermally super-insulative and flexible hybrid silica aerogel. A new generation of polymeric precursors was first synthesized for hybrid organic/inorganic silica aerogels from an epoxide ring containing a silica precursor. Ring opening polymerization (ROP) was used so as to insert flexible ether groups into the main chain. It has been demonstrated that the particulate structure of the polyether-based silica aerogel could be changed to a novel non-particulate and continuous one, by meticulous control of the thermodynamics, namely, through variations of the molecular weight of the polymeric precursor, the amount of the non-solvent, and the temperature. The study presents a new strategy to manufacture a polyether-based hybrid silica aerogel, which is fast and scalable, and also eliminates the aging process while accelerating the gelation time. This new strategy reduces the wet gel preparation time, including gelation, aging and solvent exchange, from several days to just a few seconds. However, this structure suffers from a low void fraction and wide pore size distribution. These drawbacks are then removed by chemically incorporating pre-polymerized vinyl trimethoxysilane chains. The resultant aerogels exhibit thermal superinsulation (λ = 15.9 mW·m^-1·K^-1) while providing good mechanical properties and flexibility. The polyether-based aerogels also demonstrated good performance as adsorbent material to remove organic solvents from water.