Liquid-Assisted Plasma-Enhanced Chemical Vapor Deposition of Catechol and Quinone-Functionalized Coatings: Insights into the Surface Chemistry and Morphology

Liquid-assisted plasma-enhanced chemical vapor deposition (LA-PECVD) provides a convenient approach toward the preparation of functional surfaces. In this work, the LA-PECVD approach is reported for the high deposition rate of tuneable catechol and quinone-functionalized coatings from plasma polymerization of vinyltrimethoxysilane (VTMOS) and dopamine acrylamide (DOA). Most particularly, the influence of the liquid precursor delivery rate and of the plasma power density on the chemistry and morphology of the formed layers are investigated. Precursor delivery rate and plasma power conditions are found, through mass measurement, XPS, FTIR, and Raman spectroscopy, to enable the high deposition rate of cross-linked coatings. Interestingly, the integration and conservation of the catechol functional group from the DOA monomer are highlighted through the reduction of a silver nitrate solution and silver nanoparticles formation observation via SEM/EDX. Due to the presence of oxidant species and to the bombardment of the layer with highly energetic species, quinone groups formation is likely to occur during the plasma treatment and is then highlighted via ToF-SIMS analyses of a surface successfully derivatized with a beta-lactamase. The conservation of both functional groups on the surface makes this type of layer promising for numerous applications. Quinone groups provide a real platform for the immobilization of biomolecules with various properties, e.g., antibiotics degradation, antibacterial, while the catechol groups are interesting for trapping radicals or metal ions for water treatment applications.