Synergistic antimicrobial and surface free energy of sol–gel coatings containing fluorosilanes and quaternary ammonium salts

• A two component hybrid polysiloxane was formulated and surface analyzed.
• Fluorosilane and antimicrobial additives were incorporated to modify surface.
• Inclusion of both additives provided synergistic effect on coatings properties.
• Effects arises from increase in both the micro and nanoscale roughness.
• These properties provide coating with CWS resistance and antimicrobial properties.

A need currently exists for chemical agent repellent coatings that also possess antimicrobial activity. Current coatings, primarily polyurethanes, lack chemical and antimicrobial resistance. With this in mind, herein a novel two component hybrid polysiloxane coating was prepared. Fluorosilane and quaternary ammonium salt (QAS) additives were incorporated in order to decrease the surface free energy and to impart antimicrobial activity. The inclusion of the additives independently showed a decrease in the surface free energy for the fluorosilane and antimicrobial activity for the QAS. A synergistic effect however was observed when both additives were used together in the polysiloxane. The combination of fluorosilane and QAS led to a further decrease in the surface free energy of the polysiloxane due to increases in both micro and nanoscale roughness as confirmed by confocal and AFM. Retention of antimicrobial properties was observed with log kills ranging from 3 to 5. The hybrid polysiloxane containing both additives provided a coating with enhanced chemical agent resistance and antimicrobial properties.

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