Rigid Origami via Optical Programming and Deferred Self-Folding of a Two-Stage Photopolymer.
We demonstrate the formation of shape-programmed, glassy origami structures using a single-layer photopolymer with two mechanically distinct phases. The latent origami pattern consisting of rigid, high cross-link density panels and flexible, low cross-link density creases is fabricated using a series of photomask exposures. Strong optical absorption of the polymer formulation creates depth-wise gradients in the cross-link density of the creases, enforcing directed folding which enables programming of both mountain and valley folds within the same sheet. These multiple photomask patterns can be sequentially applied because the sheet remains flat until immersed into a photopolymerizable monomer solution that differentially swells the polymer to fold and form the origami structure. After folding, a uniform photoexposure polymerizes the absorbed solution, permanently fixing the shape of the folded structure while simultaneously increasing the modulus of the folds. This approach creates sharp folds by mimicking the stiff panels and flexible creases of paper origami while overcoming the traditional trade-off of self-actuated materials that require low modulus for folding and high modulus for mechanical robustness. Using this process, we demonstrate a waterbomb base capable of supporting 1500 times its own weight.
Department of Electrical, Computer, and Energy Engineering, University of Colorado , UCB 425, Boulder, Colorado 80309, United States.
David J
DJ
Glugla
Materials Science and Engineering Program, University of Colorado , UCB 596 Boulder, Colorado 80309, United States.
Marvin D
MD
Alim
Department of Chemical and Biological Engineering, University of Colorado , UCB 596, Boulder, Colorado 80309, United States.
Keaton D
KD
Byars
Department of Ophthalmology, University of Colorado Anschutz Medical Campus , Aurora, Colorado 80045, United States.
Devatha P
DP
Nair
Department of Chemical and Biological Engineering, University of Colorado , UCB 596, Boulder, Colorado 80309, United States.
Christopher N
CN
Bowman
Department of Aerospace Engineering, University of Colorado , UCB 429, Boulder, Colorado 80309, United States.
Kurt K
KK
Maute
Department of Electrical, Computer, and Energy Engineering, University of Colorado , UCB 425, Boulder, Colorado 80309, United States.
Robert R
RR
McLeod
folding; origami; polymer sheets; shape-programmed material; stimuli-responsive materials; two-stage polymer