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Harnessing Photochemical Shrinkage in Direct Laser Writing for Shape Morphing of Polymer Sheets
Author(s) -
Bauhofer Anton A.,
Krödel Sebastian,
Rys Jan,
Bilal Osama R.,
Constantinescu Andrei,
Daraio Chiara
Publication year - 2017
Publication title -
advanced materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 10.707
H-Index - 527
eISSN - 1521-4095
pISSN - 0935-9648
DOI - 10.1002/adma.201703024
Subject(s) - microscale chemistry , morphing , materials science , fabrication , shrinkage , bending , 3d printing , planar , polymerization , laser , microstructure , polymer , nanotechnology , composite material , optics , computer science , artificial intelligence , medicine , alternative medicine , mathematics , mathematics education , computer graphics (images) , physics , pathology
Abstract Structures that change their shape in response to external stimuli unfold possibilities for more efficient and versatile production of 3D objects. Direct laser writing (DLW) is a technique based on two‐photon polymerization that allows the fabrication of microstructures with complex 3D geometries. Here, it is shown that polymerization shrinkage in DLW can be utilized to create structures with locally controllable residual stresses that enable programmable, self‐bending behavior. To demonstrate this concept, planar and 3D‐structured sheets are preprogrammed to evolve into bio‐inspired shapes (lotus flowers and shark skins). The fundamental mechanisms that control the self‐bending behavior are identified and tested with microscale experiments. Based on the findings, an analytical model is introduced to quantitatively predict bending curvatures of the fabricated sheets. The proposed method enables simple fabrication of objects with complex geometries and precisely controllable shape morphing potential, while drastically reducing the required fabrication times for producing 3D, hierarchical microstructures over large areas in the order of square centimeters.