All Publications

  • Multiple equilibrium states of a curved-sided hexagram: Part I-stability of states JOURNAL OF THE MECHANICS AND PHYSICS OF SOLIDS Lu, L., Dai, J., Leanza, S., Zhao, R., Hutchinson, J. W. 2023; 180
  • Multiple equilibrium states of a curved-sided hexagram: Part II-Transitions between states JOURNAL OF THE MECHANICS AND PHYSICS OF SOLIDS Lu, L., Dai, J., Leanza, S., Hutchinson, J. W., Zhao, R. 2023; 180
  • Liquid Crystal Elastomer - Liquid Metal Composite: Ultrafast, Untethered, And Programmable Actuation by Induction Heating. Advanced materials (Deerfield Beach, Fla.) Maurin, V., Chang, Y., Ze, Q., Leanza, S., Wang, J., Zhao, R. R. 2023: e2302765


    Liquid crystal elastomers (LCEs) are a class of stimuli-responsive materials that have been intensively studied for applications including artificial muscles, shape morphing structures, and soft robotics, due to their capability of large, programmable, and fully reversible actuation strains. To fully take advantage of LCEs, rapid, untethered, and programmable actuation methods are highly desirable. Here, we report a liquid crystal elastomer-liquid metal (LCE-LM) composite, which enables ultrafast and programmable actuations by eddy current induction heating. The composite consists of LM sandwiched between two LCE layers printed via direct ink writing (DIW). When subjected to a high-frequency alternating magnetic field, the composite is actuated in milliseconds. By moving the magnetic field, the eddy current is spatially controlled for selective actuation. Additionally, sequential actuation is achievable by programming the LM thickness distribution in a sample. With these capabilities, the LCE-LM composite is further exploited for multimodal deformation of a pop-up structure, on-ground omnidirectional robotic motion, and in-water targeted object manipulation and crawling. This article is protected by copyright. All rights reserved.

    View details for DOI 10.1002/adma.202302765

    View details for PubMedID 37656872

  • Active Materials for Functional Origami. Advanced materials (Deerfield Beach, Fla.) Leanza, S., Wu, S., Sun, X., Qi, H. J., Zhao, R. R. 2023: e2302066


    In recent decades, origami has been explored to aid in the design of engineering structures. These structures span multiple scales and have been demonstrated to be used towards various areas such as aerospace, metamaterial, biomedical, robotics, and architectural applications. Conventionally, origami or deployable structures have been actuated by hands, motors, or pneumatic actuators, which can result in heavy or bulky structures. On the other hand, active materials, which reconfigure in response to external stimulus, eliminate the need for external mechanical loads and bulky actuation systems. Thus, in recent years, active materials incorporated with deployable structures have shown promise for remote actuation of light weight, programmable origami. In this review, active materials such as shape memory polymers and alloys, hydrogels, liquid crystal elastomers, magnetic soft materials, and covalent adaptable network polymers, their actuation mechanisms, as well as how they have been utilized for active origami and where these structures are applicable is discussed. Additionally, the state-of-the-art fabrication methods to construct active origami are highlighted. The existing structural modeling strategies for origami, the constitutive models used to describe active materials, and the largest challenges and future directions for active origami research are summarized. This article is protected by copyright. All rights reserved.

    View details for DOI 10.1002/adma.202302066

    View details for PubMedID 37120795

  • Easy snap-folding of hexagonal ring origami by geometric modifications JOURNAL OF THE MECHANICS AND PHYSICS OF SOLIDS Lu, L., Leanza, S., Dai, J., Sun, X., Zhao, R. 2023; 171
  • Hexagonal Ring Origami Assemblies: Foldable Functional Structures With Extreme Packing JOURNAL OF APPLIED MECHANICS-TRANSACTIONS OF THE ASME Leanza, S., Wu, S., Dai, J., Zhao, R. 2022; 89 (8)

    View details for DOI 10.1115/1.4054693

    View details for Web of Science ID 000821123400007

  • Phase diagram and mechanics of snap-folding of ring origami by twisting INTERNATIONAL JOURNAL OF SOLIDS AND STRUCTURES Sun, X., Wu, S., Dai, J., Leanza, S., Yue, L., Yu, L., Jin, Y., Qi, H., Zhao, R. 2022; 248
  • Spinning-enabled wireless amphibious origami millirobot. Nature communications Ze, Q., Wu, S., Dai, J., Leanza, S., Ikeda, G., Yang, P. C., Iaccarino, G., Zhao, R. R. 2022; 13 (1): 3118


    Wireless millimeter-scale origami robots have recently been explored with great potential for biomedical applications. Existing millimeter-scale origami devices usually require separate geometrical components for locomotion and functions. Additionally, none of them can achieve both on-ground and in-water locomotion. Here we report a magnetically actuated amphibious origami millirobot that integrates capabilities of spinning-enabled multimodal locomotion, delivery of liquid medicine, and cargo transportation with wireless operation. This millirobot takes full advantage of the geometrical features and folding/unfolding capability of Kresling origami, a triangulated hollow cylinder, to fulfill multifunction: its geometrical features are exploited for generating omnidirectional locomotion in various working environments through rolling, flipping, and spinning-induced propulsion; the folding/unfolding is utilized as a pumping mechanism for controlled delivery of liquid medicine; furthermore, the spinning motion provides a sucking mechanism for targeted solid cargo transportation. We anticipate the amphibious origami millirobots can potentially serve as minimally invasive devices for biomedical diagnoses and treatments.

    View details for DOI 10.1038/s41467-022-30802-w

    View details for PubMedID 35701405

  • Hexagonal ring origami-Snap-folding with large packing ratio EXTREME MECHANICS LETTERS Wu, S., Dai, J., Leanza, S., Zhao, R. 2022; 53
  • Soft robotic origami crawler. Science advances Ze, Q., Wu, S., Nishikawa, J., Dai, J., Sun, Y., Leanza, S., Zemelka, C., Novelino, L. S., Paulino, G. H., Zhao, R. R. 2022; 8 (13): eabm7834


    Biomimetic soft robotic crawlers have attracted extensive attention in various engineering fields, owing to their adaptivity to different terrains. Earthworm-like crawlers realize locomotion through in-plane contraction, while inchworm-like crawlers exhibit out-of-plane bending-based motions. Although in-plane contraction crawlers demonstrate effective motion in confined spaces, miniaturization is challenging because of limited actuation methods and complex structures. Here, we report a magnetically actuated small-scale origami crawler with in-plane contraction. The contraction mechanism is achieved through a four-unit Kresling origami assembly consisting of two Kresling dipoles with two-level symmetry. Magnetic actuation is used to provide appropriate torque distribution, enabling a small-scale and untethered robot with both crawling and steering capabilities. The crawler can overcome large resistances from severely confined spaces by its anisotropic and magnetically tunable structural stiffness. The multifunctionality of the crawler is explored by using the internal cavity of the crawler for drug storage and release. The magnetic origami crawler can potentially serve as a minimally invasive device for biomedical applications.

    View details for DOI 10.1126/sciadv.abm7834

    View details for PubMedID 35353556