Upgrading the toolbox: Two-photon absorption induced cleavage of Coumarin dimers for light-based 4D printing.

The use of light for shaping and changing matter is of high relevance in polymer and material science. Here, a photopolymer method is presented, which comprises the combination of 3D photo-printing at 405 nm light and subsequent modification under two-photon absorption (TPA) conditions at 532 nm light, adding the fourth dimension. The TPA-triggered cycloreversion reaction of an intramolecular coumarin dimer (ICD) structure occurs within the absorbing material. The 3D-printable matrix does not show any degradation under the TPA conditions. With the presented photochemical tool of TPA processes inside absorbing 3D photo-printable matrices, new possibilities for post-printing modification, e. g. for smart materials, are added. This article is protected by copyright. All rights reserved.