(334e) Chemical Vapor Deposition of Ultrathin Zwitterionic Polymer Coatings

Zwitterionic polymers have revolutionized the field of coating materials, imparting desirable properties like anti-biofouling and biocompatibility to existing devices and materials. Traditional solution-based synthesis and processing methods, such as graft-from, graft-to, drop casting, and spin-coating, have been the go-to for zwitterionic polymer coatings. However, these methods pose challenges that could limit the widespread use of such coatings, such as substrate-dependent coating quality, limited conformality, and coating thickness control. To overcome these hurdles, we have pioneered an all-dry synthesis technique based on initiated Chemical Vapor Deposition (iCVD), a fresh strategy that allows for the creation of ultrathin and conformal zwitterionic polymer coatings on virtually any substrate. The all-dry synthesis scheme comprises two steps: first, the iCVD polymerization of a nitrogen-containing precursor (e.g., 4-vinylpyridine) and second, the derivatization of the iCVD polymer (e.g., with 1,3-propanesulton). Building from this synthesis strategy, our research has enabled a wider selection of the cationic moieties in a zwitterionic polymer, moving past the quaternary ammonium to pyridinium and imidazolium, which have led to new insights into the molecular design of zwitterionic polymers for applications ranging from anti-biofouling coatings to stable lithium and zinc batteries.