Synergistic antibacterial material of cetylpyridinium/Cu2+/sepiolite and its application in thermoplastic polyurethane films

Seeking non-antibiotic solutions against bacterial infections has become a global priority. Therefore, this work employs sepiolite as the carrier to load cetylpyridinium (CP⁺) and Cu²⁺, constructing a CP⁺/Cu²⁺/sepiolite (PCS) system with excellent antibacterial and application properties. Sepiolite, serving as a micro-container for storing antibacterial agents, enhances their thermal stability and realizes their “burst + sustained” release. Antibacterial agents improve the organic compatibility of sepiolite and provide a synergistic antibacterial effect. With the released antibacterial agents and contact inactivation effect, PCS at 10 mg/L and 75 mg/L achieve 100 % inactivation of Staphylococcus aureus and Escherichia coli within 120 min, respectively. Furthermore, the sepiolite carrier with an intact fibrous structure facilitates the loading-release and antibacterial activity of agents in PCS. The obtained PCS disperses uniformly in thermoplastic polyurethane and binds tightly with it, improving its mechanical properties. Film of ST-10wt%PCS with 10 wt% PCS inactivates 100 % of Staphylococcus aureus and 93.0 % of Escherichia coli in 4 h, while exhibiting superior elongation at break (263 %) and tensile strength (35 MPa) compared to the pure film (242 % and 30 MPa). Thus, it is evident that the resulting PCS holds promise for the direct use or manufacture of functional products to combat bacterial infections.