Effect of Viscoelasticity on Adhesion of Bioinspired Micropatterned Epoxy Surfaces

G. Castellanos, E. Arzt, M.M.G. Kamperman

Research output: Contribution to journalArticleAcademicpeer-review

50 Citations (Scopus)

Abstract

The effect of viscoelasticity on adhesion was investigated for micropatterned epoxy surfaces and compared to nonpatterned surfaces. A two-component epoxy system was used to produce epoxy compositions with different viscoelastic properties. Pillar arrays with flat punch tip geometries were fabricated with a two-step soft lithography process. Adhesion properties were measured with a home-built adhesion tester using a spherical sapphire probe as a counter-surface. Compared to flat controls, micropatterned epoxy samples with low visco elasticity (i.e., low damping factors) showed at least a 20-fold reduction in pull-off force per actual contact area for both low (E' = 2.3 MPa) and high (E' = 2.3 GPa) storage moduli. This antiadhesive behavior may result from poor contact formation and indicates that the adhesion performance of commonly used elastomers for dry adhesives (e.g., polydimethylsiloxane) is governed by the interfacial viscoelasticity. Adhesion significantly increased with increasing viscoelasticity. Micropatterned samples with high viscoelasticity showed a 4-fold reduction in adhesion for aspect ratio (AR) 1.1 patterns but a 2-fold enhancement in adhesion for AR 2.2 patterns. These results indicate that viscoelasticity can enhance the effect of surface patterning on adhesion and should be considered as a significant parameter in the design of artificial patterned adhesives.
Original languageEnglish
Pages (from-to)7752-7759
JournalLangmuir
Volume27
Issue number12
DOIs
Publication statusPublished - 2011

Keywords

  • pressure-sensitive-adhesives
  • biological-systems
  • aspect-ratio
  • design maps
  • contact
  • mechanics
  • force
  • failure
  • micro
  • shape

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