Shape memory in self-adapting colloidal crystals

Seungkyu Lee1,2, Heather A Calcaterra2,3, Sangmin Lee4,5, Wisnu Hadibrata6, Byeongdu Lee7, EunBi Oh1,2, Koray Aydin6, Sharon C Glotzer4,5, Chad A Mirkin8,9,10

  1. Department of Chemistry, Northwestern University, Evanston, USA.
  2. International Institute for Nanotechnology, Northwestern University, Evanston, USA.
  3. Department of Chemical and Biological Engineering, Northwestern University, Evanston, USA.
  4. Department of Chemical Engineering, University of Michigan, Ann Arbor, USA.
  5. Biointerfaces Institute, University of Michigan, Ann Arbor, USA.
  6. Department of Electrical and Computer Engineering, Northwestern University, Evanston, USA.
  7. X-ray Science Division, Argonne National Laboratory, Lemont, USA.
  8. Department of Chemistry, Northwestern University, Evanston, USA. chadnano@northwestern.edu.
  9. International Institute for Nanotechnology, Northwestern University, Evanston, USA. chadnano@northwestern.edu.
  10. Department of Chemical and Biological Engineering, Northwestern University, Evanston, USA. chadnano@northwestern.edu.

Abstract

Reconfigurable, mechanically responsive crystalline materials are central components in many sensing, soft robotic, and energy conversion and storage devices1-4. Crystalline materials can readily deform under various stimuli and the extent of recoverable deformation is highly dependent upon bond type1,2,5-10. Indeed, for structures held together via simple electrostatic interactions, minimal deformations are tolerated. By contrast, structures held together by molecular bonds can, in principle, sustain much larger deformations and more easily recover their original configurations. Here we study the deformation properties of well-faceted colloidal crystals engineered with DNA. These crystals are large in size (greater than 100 µm) and have a body-centred cubic (bcc) structure with a high viscoelastic volume fraction (of more than 97%). Therefore, they can be compressed into irregular shapes with wrinkles and creases, and, notably, these deformed crystals, upon rehydration, assume their initial well-formed crystalline morphology and internal nanoscale order within seconds. For most crystals, such compression and deformation would lead to permanent, irreversible damage. The substantial structural changes to the colloidal crystals are accompanied by notable and reversible optical property changes. For example, whereas the original and structurally recovered crystals exhibit near-perfect (over 98%) broadband absorption in the ultraviolet-visible region, the deformed crystals exhibit significantly increased reflection (up to 50% of incident light at certain wavelengths), mainly because of increases in their refractive index and inhomogeneity.

Presented By Heather A Calcaterra | ORCID iD

Physical SciencesNicholas Liao2022-10 (Oct)