Enabling Robust Self-Folding Origami by Pre-Biasing Vertex Buckling Direction

Ji Hwan Kang, Hyunki Kim, Christian D. Santangelo, Ryan C. Hayward

Research output: Contribution to journalArticlepeer-review

32 Scopus citations


Self-folding is a powerful approach to fabricate materials with complex 3D forms and advanced properties using planar patterning steps, but suffers from intrinsic limitations in robustness due to the highly bifurcated nature of configuration space around the flat state. Here, a simple mechanism is introduced to achieve robust self-folding of microscale origami by separating actuation into two discrete steps using different thermally responsive hydrogels. First, the vertices are pre-biased to move in the desired direction from the flat state by selectively swelling one of the two hydrogels at high temperature. Subsequently, the creases are folded toward their target angles by activating swelling of the second hydrogel upon cooling to room temperature. Since each vertex can be individually programmed to move upward or downward, it is possible to robustly select the desired branch even in multi-vertex structures with reasonably high complexity. This strategy provides key new principles for designing shaping-morphing materials that avoid undesired distractor states, expanding their potential applications in areas such as soft robotics, sensors, mechanical metamaterials, and deployable devices.

Original languageEnglish (US)
Article number0193006
JournalAdvanced Materials
Issue number39
StatePublished - Sep 1 2019
Externally publishedYes


  • hydrogels
  • origami
  • programmable deformation
  • self-folding
  • stimuli responsive

ASJC Scopus subject areas

  • General Materials Science
  • Mechanics of Materials
  • Mechanical Engineering


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