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Nano‐3D‐Printed Photochromic Micro‐Objects
Author(s) -
Ulrich Sebastian,
Wang Xiaopu,
Rottmar Markus,
Rossi René Michel,
Nelson Bradley J.,
Bruns Nico,
Müller Ralph,
ManiuraWeber Katharina,
Qin XiaoHua,
Boesel Luciano Fernandes
Publication year - 2021
Publication title -
small
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.785
H-Index - 236
eISSN - 1613-6829
pISSN - 1613-6810
DOI - 10.1002/smll.202101337
Subject(s) - photochromism , materials science , microfabrication , photoresist , photoisomerization , nanotechnology , fabrication , photochemistry , chemistry , isomerization , organic chemistry , catalysis , medicine , alternative medicine , pathology , layer (electronics)
Abstract Molecular photoswitches that can reversibly change color upon irradiation are promising materials for applications in molecular actuation and photoresponsive materials. However, the fabrication of photochromic devices is limited to conventional approaches such as mold casting and spin‐coating, which cannot fabricate complex structures. Reported here is the first photoresist for direct laser writing of photochromic 3D micro‐objects via two‐photon polymerization. The integration of photochromism into thiol–ene photo‐clickable resins enables rapid two‐photon laser processing of highly complex microstructures and facile postmodification using a series of donor–acceptor Stenhouse adduct (DASA) photoswitches with different excitation wavelengths. The versatility of thiol–ene photo‐click reactions allows fine‐tuning of the network structure and physical properties as well as the type and concentration of DASA. When exposed to visible light, these microstructures exhibit excellent photoresponsiveness and undergo reversible color‐changing via photoisomerization. It is demonstrated that the fluorescence variations of DASAs can be used as a reporter of photoswitching and thermal recovery, allowing the reading of DASA‐containing sub‐micrometric structures in 3D. This work delivers a new approach for custom microfabrication of 3D photochromic objects with molecularly engineered color and responsiveness.