Batch fabrication and characterization of nanostructures for enhanced adhesion

This paper describes the realization and characterization of nanofabricated organic looking polymer nanorods, “organorods,” for use in a biomimetic adhesion system. The adhesion system is inspired by the fine hair adhesive motif found in nature and best exemplified by the gecko. The meso- to nanostructure of the gecko’s foot is designed to maximize inelastic surface contact to enhance van der Waals interactions. In this work, cleanroom-based processing techniques have been used for fabrication and characterization of nanostructures for inclusion in a multi-scale system mimicking the natural adhesive. The multi-scale system consists of flexible silicon dioxide platforms, supported by a single silicon pillar, coated with ∼200 nm in diameter and ∼4 μm tall polymeric organorods. The organorod surface is altered between hydrophilic and highly-hydrophobic. The adhesive properties between the artificial surface and a 3.175 mm aluminum sphere are measured in a modified nanoindenter. Initial results indicate improved adhesion with the hydrophobic surface over the hydrophilic, further corroborating van der Waals interactions to be the operative force of adhesion and suggesting a reduced cut-off distance in the van der Waals theory.