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Harnessing Photochemical Shrinkage in Direct Laser Writing for Shape Morphing of Polymer Sheets

Bauhofer, Anton A. and Krödel, Sebastian and Rys, Jan and Bilal, Osama R. and Constantinescu, Andrei and Daraio, Chiara (2017) Harnessing Photochemical Shrinkage in Direct Laser Writing for Shape Morphing of Polymer Sheets. Advanced Materials, 29 (42). Art. No. 1703024. ISSN 0935-9648. doi:10.1002/adma.201703024.

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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.

Item Type:Article
Related URLs:
URLURL TypeDescription
Krödel, Sebastian0000-0002-9218-8578
Bilal, Osama R.0000-0003-3803-5084
Daraio, Chiara0000-0001-5296-4440
Additional Information:© 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim. Received: May 30, 2017; Revised: July 8, 2017; Published online: September 25, 2017. This work was partially funded by the Swiss National Science Foundation through grant “MechNanoTruss–Mechanical response of polymer nanotruss scaffolds” (No. 164375). The authors declare no conflict of interest.
Funding AgencyGrant Number
Swiss National Science Foundation (SNSF)164375
Subject Keywords:direct laser writing; residual stresses; self-bending; shape programming
Issue or Number:42
Record Number:CaltechAUTHORS:20170925-104553545
Persistent URL:
Official Citation:A. A. Bauhofer, S. Krödel, J. Rys, O. R. Bilal, A. Constantinescu, C. Daraio, Adv. Mater. 2017, 29, 1703024.
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:81807
Deposited By: Tony Diaz
Deposited On:25 Sep 2017 18:03
Last Modified:15 Nov 2021 19:46

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