Hierarchical Nacre Mimetics with Synergistic Mechanical Properties by Control of Molecular Interactions in Self-Healing Polymers

Angew Chem Int Ed Engl. 2015 Jul 20;54(30):8653-7. doi: 10.1002/anie.201502323. Epub 2015 Jun 10.

Abstract

Designing the reversible interactions of biopolymers remains a grand challenge for an integral mimicry of mechanically superior biological composites. Yet, they are the key to synergistic combinations of stiffness and toughness by providing sacrificial bonds with hidden length scales. To address this challenge, dynamic polymers were designed with low glass-transition temperature T(g) and bonded by quadruple hydrogen-bonding motifs, and subsequently assembled with high-aspect-ratio synthetic nanoclays to generate nacre-mimetic films. The high dynamics and self-healing of the polymers render transparent films with a near-perfectly aligned structure. Varying the polymer composition allows molecular control over the mechanical properties up to very stiff and very strong films (E≈45 GPa, σ(UTS)≈270 MPa). Stable crack propagation and multiple toughening mechanisms occur in situations of balanced dynamics, enabling synergistic combinations of stiffness and toughness. Excellent gas barrier properties complement the multifunctional property profile.

Keywords: bioinspired materials; crack propagation; nacre mimetics; sacrificial bonds; toughness.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Biomimetic Materials / chemistry*
  • Biomimetics
  • Hydrogen Bonding
  • Mechanical Phenomena
  • Nacre / chemistry*
  • Polymers / chemistry*
  • Transition Temperature

Substances

  • Nacre
  • Polymers