N-halamine biocidal coatings via a layer-by-layer assembly technique

Area of Science:

• Materials Science
• Polymer Chemistry
• Textile Engineering

Background:

• Developing effective antimicrobial textiles is crucial for infection control.
• N-halamine compounds are known for their potent biocidal properties.
• Traditional methods for applying antimicrobial agents to textiles can be limited by solvent use and covalent bonding requirements.

Purpose of the Study:

• To synthesize N-halamine copolymer precursors.
• To apply these precursors onto cotton fabric using layer-by-layer assembly.
• To evaluate the biocidal efficacy and stability of the resulting antimicrobial coatings.

Main Methods:

• Synthesis of two N-halamine copolymer precursors: poly(2,2,6,6-tetramethyl-4-piperidyl methacrylate-co-acrylic acid potassium salt) and poly(2,2,6,6-tetramethyl-4-piperidyl methacrylate-co-trimethyl-2-methacryloxyethylammonium chloride).
• Layer-by-layer (LbL) assembly technique for depositing multilayer thin films onto cotton fabric.
• Chlorination of the coated fabric using dilute household bleach to activate biocidal properties.
• Evaluation of biocidal efficacy against Staphylococcus aureus and Escherichia coli O157:H7.
• Assessment of coating stability against washing and UVA light exposure.

Main Results:

• The layer-by-layer assembly successfully coated cotton fabric with N-halamine precursor polymers.
• Chlorinated N-halamine coated fabrics demonstrated significant inactivation of both Staphylococcus aureus and Escherichia coli O157:H7 within 15 minutes.
• Unchlorinated control samples showed no significant biocidal activity.
• The N-halamine coatings exhibited superior stability towards washing but moderate stability towards UVA light exposure compared to other N-halamine compounds.
• The LbL technique allowed for the attachment of N-halamine precursors without covalent tethers, offering greater structural design flexibility.
• The use of water-soluble ionic precursors eliminates the need for organic solvents, making the process environmentally friendly.

Conclusions:

• Layer-by-layer assembly is an effective method for creating durable, water-soluble N-halamine precursor coatings on cellulose-based textiles.
• The activated N-halamine coatings provide potent and rapid biocidal activity against common bacteria.
• These findings present a promising, solvent-free approach for developing advanced antimicrobial textiles with potential applications in healthcare and beyond.