Understanding the role of crosslink density and linear viscoelasticity on the shear failure of pressure-sensitive-adhesives

Pressure-sensitive-adhesives (PSAs) are ubiquitous in electronic, automobile, packaging, and biomedical applications due to their ability to stick to numerous surfaces without undergoing chemical reactions. Although these materials date back to the 1850s with the development of surgical tapes based...

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Bibliographic Details
Published in:Soft matter 2023-08, Vol.19 (32), p.688-696
Main Authors: Arrowood, Anthony, Ansari, Mohammad A, Ciccotti, Matteo, Huang, Rui, Liechti, Kenneth M, Sanoja, Gabriel E
Format: Article
Language:English
Subjects:
Acrylic acid
Adhesives
Aluminum
Biomedical materials
Chemical reactions
Condensed Matter
Crosslinking
Density
Electronic packaging
Load transfer
Mechanical properties
Natural rubber
Packaging
Physics
Shear lag
Shear strength
Shear stress
Soft Condensed Matter
Viscoelasticity
Weight reduction
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Summary:Pressure-sensitive-adhesives (PSAs) are ubiquitous in electronic, automobile, packaging, and biomedical applications due to their ability to stick to numerous surfaces without undergoing chemical reactions. Although these materials date back to the 1850s with the development of surgical tapes based on natural rubber, their resistance to shear loads remains challenging to predict from molecular design. This work investigates the role of crosslink density on the shear resistance of model PSAs based on poly(2-ethylhexyl acrylate- co -acrylic acid) physically crosslinked with aluminum acetylacetonate. The key result is that crosslinking PSAs leads to notable stress concentrations ahead of the peel front, as well as a transition from cohesive to adhesive failure. The shear stress distributions, as evaluated by means of a linearly viscoelastic shear lag model, suggest that this transition is related to the evolution of the ratio of the load transfer length to the bond length as dictated by the mechanical properties of the backing and adhesive layers, and the geometry of the tape. Entangled and chemically crosslinked polymer networks can resist instantaneous debonding by dissipating strain energy, and sustain shear loads by evolving a stable stress concentration at the peel front.
ISSN:1744-683X
1744-6848
DOI:10.1039/d3sm00562c