Why Aerogels?
What are aerogels?
Aerogels are fascinating materials with a highly porous structure consisting of more than 95% air. The pores are more than a factor of 1000 smaller than a human hair. At the same time, the solid material from which the structure is built is extremely fine and light.
Aerogels are produced from a gel precursor similar to a solid jelly by gently removing the liquid from the gel in a special high-pressure drying process so that the extremely fine structure is retained. The structure can consist of a wide variety of precursors such as mineral systems, synthetic polymers or biopolymers.
Aerogels as products
Aerogels made of silica in the form of blankets or particles have been available as commercial products for many decades. At BASF, the aerogel-it founders developed commercial aerogel boards based on polyurethane (SLENTITE and thin PU aerogel sheets). The team now concentrates on developing the first commercial aerogel materials based on biopolymers.
Manufacturing of aerogels
Since the production of aerogels is complex and comparatively cost-intensive due to the special process steps involved, the team at aerogel-it is developing next-generation aerogel manufacturing processes in order to reduce costs in the medium term.
Electron microscope image of polymer aerogel.
What are aerogels used for?
The special structure of aerogels leads to a variety of interesting properties that can be used for different applications.
Thermal superinsulation
Thermal insulation materials usually consist to a large extent of gas such as air or special propellants with good insulative properties. Their thermal insulation is therefore largely determined by these gases, which conduct heat much more poorly than the solid material of which the thermal insulation material is made. Nevertheless, the gases exhibit a certain minimum thermal conductivity, which sets a physical limit that cannot be overcome.
Aerogels also contain more than 95% of air. However, due to the very fine pores, the thermal conduction of this air is strongly suppressed thanks to a physical effect (Knudsen effect). Therefore aerogels can be used to build up significantly thinner insulation layers and thus save valuable space compared to conventional thermal insulation. Conversely, comparatively high thermal insulation efficiency is possible with aerogels in a given limited installation space. Both aspects are highly relevant for new buildings in expensive inner-city locations or for the energetic refurbishment of existing buildings and monuments. The second aspect applies in particular to interior insulation, where as much room area as possible is to be preserved.
Vacuum insulation panels represent a special case of super thermal insulation. In these products, heat conduction via the gas is greatly reduced by means of a vacuum.
The aerogel-it team is working on bioaerogel products as green and sustainable thermal superinsulation for a wide range of industries.
Load and release
Due to their highly porous structure, aerogels are interesting as carrier materials for liquids. Their particularly low density leads to especially high loading capacity. Since the pores of aerogels are very fine, a liquid introduced into the aerogel cannot easily be forced out of the structure by compression - in contrast to open-cell foams. Liquids loaded onto aerogels thus behave like solids and can be handled and dispensed with corresponding ease.
The aerogel-it team is developing bioaerogel products as green and sustainable carrier materials for liquids.
Rheology modification
The highly porous structure and large surface area of aerogels leads to strong physical interactions with fluids surrounding them. Aerogels are therefore particularly suitable as rheology modifiers to change the viscous behavior of fluid phases.
The aerogel-it team is developing bioaerogel products as green and sustainable rheology modifiers.