Laser induced instantaneous gelation: aerogels for 3D printing

We present the synthesis of polymer cross-linked silica alcogels in a matter of seconds by illuminating the solution of TEOS, hexanedioldiacrylate, Eosin Y and amine with a laser beam (lambda = 532 nm). The heat of polymerization triggers gelation instantly. We demonstrate printing of 3D letters on different substrates using this technique. The physical properties of the 3D printed samples are comparable to conventionally prepared cross-linked silica aerogels, i.e., shrinkage (10.4%), density (0.56 g cm(-3)), Young's modulus (81.3 MPa) and BET surface area (155.3 m(2) g(-1)). An important aspect of this rapid gelation is that it allows 3D printing/lithography of reinforced silica aerogel material without using a mould.