Tree frog-inspired nanopillar arrays for enhancement of adhesion and friction

TL;DR

This paper presents bioinspired nanopillar arrays modeled after tree frog toe pads, demonstrating enhanced adhesion and friction for potential use in climbing robots and medical devices.

Contribution

It introduces a new mold process to create tightly packed polycaprolactone nanorod arrays inspired by tree frog keratin nanopillars, improving adhesion and friction performance.

Findings

Nanorod arrays outperform micropillar arrays on various surfaces.

Bonding increases nanorod stiffness, mainly boosting friction.

Design principles derived from frog toe pads guide new adhesive development.

Abstract

Bioinspired structure adhesives have received increasing interest for many applications, such as climbing robots and medical devices. Inspired by the closely packed keratin nanopillars on the toe pads of tree frogs, tightly arranged polycaprolactone nanorod arrays are prepared by mold process and chemical modification. Nanorod arrays show enhanced adhesion and friction on both smooth and rough surfaces compared to the arrays with hexagonal micropillars. The bonding of nanorods results in a larger stiffness of the nanorod surface,contributing mainly to friction rather than adhesion. The results suggest the function of closely packed keratin nanopillars on the toe pad of tree frogs and offer a guiding principle for the designing of new structured adhesives with strong attaching abilities.