Evaluation of the Durability of Slippery, Liquid-Infused Porous Surfaces in Different Aggressive Environments: Influence of the Chemical-Physical Properties of Lubricants

Federico Veronesi,Guia Guarini,Alessandro Corozzi,Mariarosa Raimondo

doi:10.3390/coatings11101170

Abstract

Liquid-repellent surfaces have been extensively investigated due to their potential application in several fields. Superhydrophobic surfaces achieve outstanding water repellence, however their limited durability in severe operational conditions hinders their large-scale application. The Slippery, Liquid-Infused Porous Surface (SLIPS) approach solves many of the durability problems shown by superhydrophobic surfaces due to the presence of an infused liquid layer. Moreover, SLIPS show enhanced repellence towards low surface tension liquids that superhydrophobic surfaces cannot repel. In this perspective, SLIPS assume significant potential for application in harsh environments; however, a systematic evaluation of their durability in different conditions is still lacking in the literature. In this work, we report the fabrication of SLIPS based on a ceramic porous layer infused with different lubricants, namely perfluoropolyethers with variable viscosity and n-hexadecane; we investigate the durability of these surfaces by monitoring the evolution of their wetting behavior after exposure to severe environmental conditions like UV irradiation, chemically aggressive solutions (acidic, alkaline, and saline), and abrasion. Chemical composition and viscosity of the infused liquids prove decisive in determining SLIPS durability; especially highly viscous infused liquids deliver enhanced resistance to abrasion stress and chemical attack, making them candidates for applicable, long-lasting liquid-repellent surfaces.

Highlights

We report the fabrication of SLIPS infused with different lubricants and study the evolution of their wetting properties after testing in several conditions, namely UV irradiation, immersion in chemically aggressive solutions, and abrasion
These results suggest that hexadecane-infused SLIPS are not ideal the increase in for applications in which the surface is exposed to air for prolonged time, due to the high candidates applications in which the surface is exposed air for prolonged time, due evaporationfor rate of the lubricant
We reported the fabrication of SLIPS based on a nanostructured, porous alumina coating infused with low surface tension lubricants with different chemical composition (PFPE, n-hexadecane) and viscosity

Summary

Introduction

Liquid-repellent surfaces have drawn huge interest in the last years due to their inherent self-cleaning properties [1,2,3] and other potential related advantages e.g., antior de-icing properties [4,5,6], drag and friction reduction [7,8,9], and anti-fouling behavior [10,11]. By coupling the creation of micro/nanoscale surface features with the tailoring of surface chemical composition to achieve low surface energy, superhydrophobic surfaces can be obtained [13,14] These materials are characterized by high water contact angles, i.e., larger than 150◦ , and high mobility of water drops that are placed on their surface. The scientific community started to design surfaces with simultaneous repellence to water (i.e., hydrophobicity) and other liquids, mainly non-polar oils (i.e., oleophobicity)

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Conclusion