Switchable Adhesion via Subsurface Pressure Modulation

Amir Mohammadi Nasab, Aoyi Luo, Siavash Sharifi, Siavash Sharifi, Kevin T. Turner, Wanliang Shan, Wanliang Shan

Research output: Contribution to journalArticle

Abstract

Materials and devices with tunable dry adhesion have many applications, including transfer printing, climbing robots, and gripping in pick-and-place processes. In this paper, a novel soft device to achieve dynamically tunable dry adhesion via modulation of subsurface pneumatic pressure is introduced. Specifically, a cylindrical elastomer pillar with a mushroom-shaped cap and annular chamber that can be pressurized to tune the adhesion is investigated. Finite element-based mechanics models and experiments are used to design, understand, and demonstrate the adhesion of the device. Specifically, the device is designed using mechanics modeling such that the pressure applied inside the annular chamber significantly alters the stress distribution at the adhered interface and thus changes the effective adhesion strength. Devices made of polydimethylsiloxane (PDMS) with different elastic moduli were tested against glass, silicon, and aluminum substrates. Adhesion strengths (σ0) ranging from ∼37 kPa (between PDMS and glass) to ∼67 kPa (between PDMS and polished aluminum) are achieved for the nonpressurized state. For all cases, regardless of the material and roughness of the substrates, the adhesion strength dropped to 40% of the strength of the nonpressurized state (equivalent to a 2.5× adhesion switching ratio) by increasing the chamber pressure from 0.3σ0 to 0.6σ0. Furthermore, the strength drops to 20% of the unpressurized strength (equivalent to a 5× adhesion switching ratio) when the chamber pressure is increased to σ0.

Original languageEnglish (US)
Pages (from-to)27717-27725
Number of pages9
JournalACS Applied Materials and Interfaces
Volume12
Issue number24
DOIs
StatePublished - Jun 17 2020

Keywords

  • dry adhesives
  • finite element analysis
  • mechanics modeling
  • subsurface pressure modulation
  • switchable adhesion

ASJC Scopus subject areas

  • Materials Science(all)

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  • Cite this

    Mohammadi Nasab, A., Luo, A., Sharifi, S., Sharifi, S., Turner, K. T., Shan, W., & Shan, W. (2020). Switchable Adhesion via Subsurface Pressure Modulation. ACS Applied Materials and Interfaces, 12(24), 27717-27725. https://doi.org/10.1021/acsami.0c05367