aerogelejä

Aerogels are a class of synthetic porous ultralight materials derived from a gel, in which the liquid component of the gel has been replaced by a gas. The result is a solid with extremely low density and low thermal conductivity. Aerogels are often referred to as "frozen smoke," "solid air," or "blue smoke," due to their ethereal appearance and low density.

The first aerogels were produced in the 1930s by Samuel Stephens Kistler. They are typically made from silica, but can also be made from other materials such as alumina, chromia, tin dioxide, and even carbon. The process of creating an aerogel involves a sol-gel process, followed by supercritical drying. This drying method prevents the collapse of the gel's delicate nanostructure, preserving its porous network.

Aerogels possess remarkable properties. Their density can be as low as 0.0011 g/cm³, making them lighter than many gases. Their high porosity (over 99%) and interconnected pore structure lead to exceptional insulating capabilities, making them ideal for thermal insulation in applications ranging from aerospace to building materials. They also exhibit good mechanical strength despite their low density and can be transparent or opaque depending on their composition and processing.

Current and potential applications for aerogels are diverse. They are used in high-performance insulation for spacecraft, in windows for energy-efficient buildings, as catalysts in chemical processes, and as filters. Their unique properties also make them candidates for use in advanced sensors, transparent conductive films, and even as matrices for drug delivery systems. Research continues to explore new ways to synthesize and utilize these extraordinary materials.