Changes in the Antibacterial Performance of Polymer-Based Nanocomposites Induced by Additive Manufacturing Processing

Area of Science:

• Materials Science
• Nanotechnology
• Biomaterials Engineering

Background:

• Air conditioners can harbor bacteria, necessitating antimicrobial filters.
• Copper nanoparticles (Cu NPs) integrated into polymers offer potential antibacterial properties.
• Poly(lactic acid) (PLA) and polyurethane (TPU) are common polymer matrices for such applications.

Purpose of the Study:

• To develop customized air conditioner filters with enhanced antibacterial performance using Cu NP-reinforced PLA and TPU.
• To investigate the impact of fused filament fabrication (FFF) processing on the nanocomposite's properties and antibacterial efficacy.

Main Methods:

• Fabrication of Cu NP-reinforced PLA and TPU nanocomposite filaments.
• Characterization using X-ray photoelectron spectroscopy (XPS) and micro-computer tomography (μ-CT).
• Evaluation of antibacterial activity using solid-state diffusion (mimicking dry air conditioner filters) and liquid tests.

Main Results:

• XPS confirmed the presence of Cu nanoparticles in various oxidation states (Cu⁰, Cu⁺, Cu²⁺) on the filament surface.
• FFF processing led to the migration of Cu nanoparticles, making them largely absent from the surface, as confirmed by μ-CT.
• Antibacterial activity was observed in liquid tests, but significantly reduced in solid-state diffusion tests after processing due to Cu migration.

Conclusions:

• While Cu NP-reinforced nanocomposites show initial promise for antibacterial applications, processing methods like FFF can compromise surface-level efficacy.
• Further research is needed to develop nanocomposite materials that maintain antimicrobial activity after processing and in dry environments.
• The study provides insights into material design for effective antimicrobial filters in air conditioning systems.