Nature‐Inspired Substrate‐Independent Omniphobic and Antimicrobial Slippery Surfaces

Abstract

Inspired by the carnivorous Nepenthes pitcher plant, a range of highly liquid repellent lubricant‐infused surfaces has been devised (low water droplet contact angle hysteresis and sliding angle values). This entails matching functional pulsed plasma polymer nanolayers with appropriate slippery lubricants. A molecular‐level structure–behavior relationship is developed, highlighting the importance of favorable aromatic–aliphatic intermolecular interactions between the coating and lubricant. Fluorinated lubricant‐infused pulsed plasma polymer nanocoatings resist wetting by liquids, spanning a wide range of surface tensions (including pentane, motor oil, and water, i.e., omniphobicity). In the case of natural antimicrobial compound‐infused functional plasma polymer surfaces (e.g., the essential oil cinnamaldehyde), multifunctional performance is attained combining high liquid repellency (self‐cleaning) with simultaneous strong antibacterial activity against both Gram‐positive Staphylococcus aureus and Gram‐negative Escherichia coli (log10 reduction > 7). In addition, these lubricant‐infused functional pulsed plasma polymer surfaces easily repel a variety of everyday liquids (including foodstuffs such as tomato ketchup and honey).

Fabrication of Omniphobic‐Omniphilic Micropatterns using GPOSS‐PDMS Coating

“…The core method of our approach is based on a previously reported NP‐GLIDE procedure designed for protective applications, which we adopted and modified to achieve patterning. [ 6 ] First, we reproduced the procedure. GPOSS was modified using linear amino‐functionalized PDMS fragments by reacting GPOSS with PDMS‐NH 2 in butyl acetate solvent at 120 °C for 1.5 h ( Figure A(i)).…”

“…Special wettability properties allow their application as anti-icing, [4] self-cleaning, [5] and anti-biofouling surfaces. [6] To date, several methods have been developed to construct omniphobic surfaces. [7][8][9][10] These include slippery liquid-infused porous surfaces (SLIPS), [8] slippery omniphobic covalently attached liquid (SOCAL), [9] and NanoPools of a Grafted Lubricating Liquid Ingredient for Dewetting Enablement (NP-GLIDE).…”

A Bifunctional Spray Coating Reduces Contamination on Surfaces by Repelling and Killing Pathogens

“…A recently developed coating consisting of hydroxyl-terminated quaternary ammonium salts enriched on a polyurethane coating (antifouling and antibacterial) showed immediate contact killing, corresponding to a 98.6% antibacterial activity with S. aureus ; however, water contact angle measurements were as low as 100° . To address the latter issues, studies have recently focused on omniphobic coatings with superior repellency to high and low surface tension liquids and excellent antimicrobial activity. − For example, polystyrene-based porous structures infiltrated with silicone oil (antifouling) and modified with 3-(trimethoxysilyl)­propyl dimethyl undecyl ammonium chloride (antibacterial) displayed sliding angle values less than 5° and a bacterial repellency of up to 98% with S. aureus. Despite the superior repellency and excellent antimicrobial activity of these lubricant-infused coatings, , their practical use for surface coatings is limited by the low stability and durability of the lubricant layer but more importantly the impracticality of an oil layer on frequently touched surfaces.…”

Antibiofouling Slippery Liquid Impregnated Pulsed Plasma Poly(styrene) Surfaces

“…[52,53] More recently, slippery surfaces have been fabricated utilizing favorable intermolecular aromaticaliphatic interactions, for example between pulsed plasma deposited poly(styrene) nanocoatings and impregnated oils. [54][55][56] Aromatic-aliphatic liquid impregnated slippery surfaces negate the requirement for porous structures associated with conventional SLIPS (Slippery Liquid Infused Porous Surfaces), which can be costly and complex to fabricate. Key advantages of pulsed plasmachemical deposition include rapid single-step, ambient conditions, solventless, 3D conformal coatings, substrate-independent, strong adhesion, low energy consumption, minimal waste products, and industrial scalability.…”