A Caltech Library Service

Knots are not for naught: Design, properties, and topology of hierarchical intertwined microarchitected materials

Moestopo, Widianto P. and Shaker, Sammy and Deng, Weiting and Greer, Julia R. (2023) Knots are not for naught: Design, properties, and topology of hierarchical intertwined microarchitected materials. Science Advances, 9 (10). Art. No. eade6725. ISSN 2375-2548. PMCID PMC9995035. doi:10.1126/sciadv.ade6725.

[img] PDF - Published Version
Creative Commons Attribution.


Use this Persistent URL to link to this item:


Lightweight and tough engineered materials are often designed with three-dimensional hierarchy and interconnected structural members whose junctions are detrimental to their performance because they serve as stress concentrations for damage accumulation and lower mechanical resilience. We introduce a previously unexplored class of architected materials, whose components are interwoven and contain no junctions, and incorporate micro-knots as building blocks within these hierarchical networks. Tensile experiments, which show close quantitative agreements with an analytical model for overhand knots, reveal that knot topology allows a new regime of deformation capable of shape retention, leading to a ~92% increase in absorbed energy and an up to ~107% increase in failure strain compared to woven structures, along with an up to ~11% increase in specific energy density compared to topologically similar monolithic lattices. Our exploration unlocks knotting and frictional contact to create highly extensible low-density materials with tunable shape reconfiguration and energy absorption capabilities.

Item Type:Article
Related URLs:
URLURL TypeDescription InCaltech News CentralArticle
Moestopo, Widianto P.0000-0002-7617-4280
Shaker, Sammy0000-0003-1751-4908
Deng, Weiting0000-0003-0984-8027
Greer, Julia R.0000-0002-9675-1508
Additional Information:© 2023 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works. Distributed under a Creative Commons Attribution License 4.0 (CC BY). We thank W. Zhang for help with fabrication of the pillar tensile tip, as well as P. Samantaray and J. Evans for assistance in XPS interpretation and collection. XPS data were collected at the Molecular Materials Research Center in the Beckman Institute at the California Institute of Technology. The authors also acknowledge the financial support from the National Science Foundation through the Graduate Research Fellowship Program (W.P.M.), the Merkin Institute for Translational Research through an Innovation Seed grant (S.S.), the UCLA-Caltech Medical Scientist Training Program (MSTP) through the National Institutes of Health (NIH) NIGMS training grant T32 GM008042 (S.S.), the Vannevar Bush Faculty Fellowship (J.R.G.), and the Office of Naval Research (ONR) grant N00014-22-1-2484. Part of this work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under contract DE-AC52-07NA27344 (LLNL-JRNL-843684). Author contributions: W.P.M. and J.R.G. conceptualized the study. W.P.M., S.S., and W.D. fabricated the samples. W.P.M. designed the samples and analyzed all data. W.P.M. and W.D. conducted the mechanical experiments. S.S. performed the UV irradiation experiments and analyzed corresponding data. W.P.M. and J.R.G. supervised the project. W.P.M., S.S., W.D., and J.R.G. discussed the findings and wrote the manuscript. Data and materials availability: All data needed to evaluate the conclusions in the paper are present in the paper and/or the Supplementary Materials. The authors declare that they have no competing interests.
Group:Richard N. Merkin Institute for Translational Research
Funding AgencyGrant Number
NSF Graduate Research FellowshipUNSPECIFIED
Caltech Merkin Institute for Translational ResearchUNSPECIFIED
UCLA-Caltech Medical Scientist Training ProgramUNSPECIFIED
NIH Predoctoral FellowshipT32 GM008042
Vannever Bush Faculty FellowshipUNSPECIFIED
Office of Naval Research (ONR)N00014-22-1-2484
Department of Energy (DOE)DE-AC52-07NA27344
Issue or Number:10
PubMed Central ID:PMC9995035
Record Number:CaltechAUTHORS:20230310-60798000.1
Persistent URL:
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:119913
Deposited By: George Porter
Deposited On:10 Mar 2023 20:00
Last Modified:10 May 2023 22:14

Repository Staff Only: item control page