Self-Assembled Asperities for Pressure Tunable Adhesion

Published

December 16, 2022

Author(s)

Naomi Deneke, Jamie Booth, Edwin P. Chan, Chelsea S. Davis

Abstract

Control of adhesive strength is important in applications such as soft robotics, pick-and-place manufacturing, flexible and wearable devices, and transfer printing. Due to the diversity of material types, these systems can potentially benefit from adhesive materials with controllable adhesion strength that is also scalable. While there are materials with discrete switchability between high and low adhesion states, a versatile and scalable design of an adhesive with continuously variable adhesion strength remains a challenge. In this work, we present a highly tunable and scalable pressure tunable adhesive (PTA) that is based on the self-assembly of stiff microscopic asperities on an elastomeric substrate. We demonstrate that the adhesion strength of the PTA increases with the applied maximum compressive preload due to the unique contact formation mechanism in the presence of the asperities. Specifically, the separation load increases from 0.4 mN to 30 mN by increasing the applied pressure when patterned with small asperities versus 2 mN to 22 mN when patterned with large asperities. Using a linear elastic fracture mechanics model, we show that adhesion hysteresis is necessary for the observation of preload-sensitive tunability of performance for our materials. Finally, we demonstrate the utility of PTA for pick-and-place material handling that is attributed to its ability to precisely control adhesion strength via applied pressure. We envision that this concept of the pressure tunable adhesion is sufficiently scalable and broadly applicable to a variety of material systems having different mechanical or surface properties to achieve a tailored pressure-tunable response.

Citation

Advanced Materials

Pub Type

Journals

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Keywords

polymers, adhesion, contact mechanics, dewetting

Citation

Deneke, N. , Booth, J. , Chan, E. and Davis, C. (2022), Self-Assembled Asperities for Pressure Tunable Adhesion, Advanced Materials, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=934640 (Accessed April 25, 2024)