Amphiphilic Copolymer Thin Films with Short Fluoroalkyl Side Chains for Antibiofilm Properties at the Solid–Liquid–Air Interface

Biofouling is a critical problem that limits numerous technologies including water desalination and marine transportation. The existing solutions, such as copper-based paint to mitigate ship hull fouling, are known to harm aquatic species. Although hydrophilic and zwitterionic materials have demonstrated great promise in resisting the formation of biofilms, they demonstrated limited effectiveness at the solid–liquid–air interface, the location most prone to biofilm formation by motile bacteria. While an amphiphilic copolymer comprising a statistical mixture of zwitterionic and fluorinated units exhibited excellent antifouling performance at the triple interface, the long-fluorinated side chain raises concerns regarding bioaccumulation. Here, two amphiphilic copolymers, each made of a pyridinium-based zwitterionic and hydrophobic repeat units with a short fluorinated chain (1 H,1 H,2 H,2 H -perflurooctyl and 2,2,3,4,4,4-hexafluorobutyl groups), were synthesized using initiated chemical vapor deposition. Fineman–Ross analysis demonstrated the formation of random copolymers with a preference for 4-vinylpyridine incorporation. The antibiofilm performance remained good for both hydrophobic chains: amphiphilic copolymers outperformed pure zwitterionic chemistry by 43.8 and 39.3%, as demonstrated using Pseudomonas aeruginosa that forms biofilms at the triple interface. The amphiphilic coatings reported here can be used to prevent biofilm formation at the triple interface in marine transportation, food manufacturing, and medical devices, while avoiding the environmental concerns related to perfluoroalkyl substances.