Achieving Ultra-Omniphilic Wettability on Copper Using a Facile, Scalable, Tuned Bulk Micromanufacturing Approach

Abstract

Altering the wetting characteristics of copper will positively impact numerous practical applications. The contact angle (CA) of a water droplet on the polished copper surface is usually between 70 deg and 80 deg. This paper discusses a facile, scalable, tuned bulk micromanufacturing approach for altering the surface topology of copper concomitantly at the micro- and nano-length scales, and thus significantly influence its wetting characteristics. The resultant copper surfaces were found to be robust, nontoxic, and exhibited ultra-omniphilicity to various industrial liquids. This extreme wetting ability akin to a paper towel (CA of zero for multiple liquids) was achieved by tuning the bulk micromanufacturing process to generate connected hierarchical micro- and nano-roughness with nanocavities within the embryos of microcavities. With an adsorbed coating of ester, the same ultra-omniphilic copper surfaces were found to exhibit robust super-hydrophobicity (CA ∼ 152 deg for water).