Princess and the Pea at the nanoscale: Wrinkling and delamination of graphene on nanoparticles

TL;DR

This study investigates how graphene membranes wrinkle and delaminate when placed on nanoparticle-decorated substrates, revealing critical behaviors relevant for strain-engineering electronic properties.

Contribution

It provides a detailed experimental and theoretical analysis of wrinkling and delamination phenomena in graphene on nanoparticle substrates, highlighting the transition from adhesion to delamination.

Findings

Wrinkling forms a percolating network at high nanoparticle density.

Global delamination occurs with increased graphene thickness.

The behaviors are explained by a continuum elastic model.

Abstract

Thin membranes exhibit complex responses to external forces or geometrical constraints. A familiar example is the wrinkling, exhibited by human skin, plant leaves, and fabrics, resulting from the relative ease of bending versus stretching. Here, we study the wrinkling of graphene, the thinnest and stiffest known membrane, deposited on a silica substrate decorated with silica nanoparticles. At small nanoparticle density monolayer graphene adheres to the substrate, detached only in small regions around the nanoparticles. With increasing nanoparticle density, we observe the formation of wrinkles which connect nanoparticles. Above a critical nanoparticle density, the wrinkles form a percolating network through the sample. As the graphene membrane is made thicker, global delamination from the substrate is observed. The observations can be well understood within a continuum elastic model and have important implications for strain-engineering the electronic properties of graphene.