From fibrils to toughness: Multi-scale mechanics of fibrillating interfaces in stretchable electronics

O. van der Sluis, T. Vermeij, J. Neggers, B. Vossen, M. van Maris, J. Vanfleteren, M.G.D. Geers, J.P.M. Hoefnagels

Research output: Contribution to journalArticlepeer-review

4 Citations (Scopus)
126 Downloads (Pure)

Abstract

Metal-elastomer interfacial systems, often encountered in stretchable electronics, demonstrate remarkably high interface fracture toughness values. Evidently, a large gap exists between the rather small adhesion energy levels at the microscopic scale ('intrinsic adhesion') and the large measured macroscopic work-of-separation. This energy gap is closed here by unravelling the underlying dissipative mechanisms through a systematic numerical/experimental multi-scale approach. This self-containing contribution collects and reviews previously published results and addresses the remaining open questions by providing new and independent results obtained from an alternative experimental set-up. In particular, the experimental studies on Cu-PDMS (Poly(dimethylsiloxane)) samples conclusively reveal the essential role of fibrillation mechanisms at the micro-meter scale during the metal-elastomer delamination process. The micro-scale numerical analyses on single and multiple fibrils show that the dynamic release of the stored elastic energy by multiple fibril fracture, including the interaction with the adjacent deforming bulk PDMS and its highly nonlinear behaviour, provide a mechanistic understanding of the highwork-of-separation. An experimentally validated quantitative relation between the macroscopic work-of-separation and peel front height is established from the simulation results. Finally, it is shown that a micro-mechanically motivated shape of the traction-separation law in cohesive zone models is essential to describe the delamination process in fibrillating metal-elastomer systems in a physically meaningful way.

Original languageEnglish
Article number231
Number of pages19
JournalMaterials
Volume11
Issue number2
DOIs
Publication statusPublished - 2 Feb 2018

Keywords

  • Cohesive zone
  • Fibrillation
  • Fracture process zone
  • Interface delamination
  • Multi-scale analysis
  • PDMS
  • Peel test
  • Stretchable electronics
  • Traction-separation law

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