Debonding of a soft adhesive fibril in contact with an elastomeric pillar

TL;DR

This study investigates the debonding behavior of soft adhesive fibrils on elastomeric pillars, revealing power-law relationships and viscoelastic effects crucial for understanding adhesive peeling mechanisms.

Contribution

It provides experimental evidence of scaling laws for fibril debonding and introduces viscoelastic effects at the debonding line, advancing the understanding of soft adhesive fibril failure.

Findings

Power laws for maximum force and critical elongation as a function of pillar diameter.

Observation of viscoelastic digitations at the debonding line for large pillars.

Wavelength and penetration length consistent with elastic models.

Abstract

The debonding criterion of fibrils of soft adhesive materials is a key element regarding the quantitative modelisation of pressure sensitive adhesive tapes peeling energy. We present in this article an experimental study of the detachment of a commercial acrylic adhesive tape from the top surface of a single micrometric pillar of PDMS elastomer. During an experiment, the pillar and the adhesive, after being put in contact, are separated at a constant displacement rate, resulting in the formation, the elongation and the final detachment of a fibril of adhesive material. A systematic study allows us to uncover power laws for the maximum force and the critical elongation of the fibril at debonding as a function of the diameter of the cylindrical pillar which controls the diameter of the fibril. The scaling law evidenced for the critical elongation appears as a first step toward the understanding of the debonding criterion of fibrils of soft adhesive materials. In addition, viscoelastic digitation at the triple debonding line is observed during detachment for large pillar diameters. The wavelength and penetration length of the fingers that we report appear to be consistent with existing models based on pure elastic mechanical response.