Rapid fabrication of hybrid aerogels and 3D printed porous materials

Abstract

In this manuscript, methods will be reviewed that alleviate or solve processing issues of aerogels. Techniques will be described that allow one-pot, rapid synthesis of both native-aerogels and mechanically reinforced-aerogels, as well as porous oxide monoliths with hierarchical pore size distribution. Farther, techniques will be reviewed that allow fabrication of inhomogeneous/anisotropic porous monoliths. Techniques will be described that allow to reinforce or functionalize selected regions of monoliths. These techniques are photolithographic in nature and allow to fabricate a wide variety of structures, including honeycombs and functionally graded materials. These materials consist of functionalized and/or mechanically reinforced regions embedded into an otherwise native aerogels and they will be termed as “hybrid”. Finally, techniques will be reviewed that alleviate or solve geometrical constraints. Typically, porous materials are produced by pouring a sol into a mold. Techniques will be presented that allow additive manufacturing of porous materials. It will be shown that technical issues likely prevent large-scale additive manufacturing of oxide aerogels. However, techniques are available and will be discussed which allow additive manufacturing of porous polymeric structures.