Ren Liu,Junchao Zheng,Zhiquan Li,Jingcheng Liu,Xiaoya Liu
A facile method to prepare surface self-concentration antibacterial coating with contact-killing mechanism was developed. Photo curable quaternary ammonium compound QAC bearing a 16-carbon alkyl chain and a terminal methacrylate was synthesized as reactive antibacterial additive. After UV irradiation, QAC was crosslinked in the soy-based coating matrix. With proper amounts of QAC, the UV cured coatings exhibited good properties such as high glossiness, good hardness and fine adhesion to cherrywood substrates. The self-concentration property of QAC on the cured coating surface, which is beneficial to reserve the physical properties of the bulk materials and to improve the surface antibacterial activity, was confirmed by fluorescence and X-ray photoelectron spectroscopy. Moreover, the introduction of QAC provided the coatings with superhydrophilicity property as well as good anti-fog capacity. The coatings with 8 wt% of QAC (charge density = 8.6 mol cm−2) exhibited almost 100% antibacterial activity against Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli by 5 log reduction. The contact-killing mechanism of coatings was confirmed via the zone of inhibition tests. The straightforward preparation combined with excellent antibacterial property makes the QAC containing coatings quite promising in antibacterial coatings realm and is suitable for industrial-scale manufacturing.
Multifunctional polyurethane based on polysiloxane tethered cationic biocides was designed for fouling resistance and antibacterial objectives. Quaternary ammonium salt (QAS) functionalized hydroxy-terminated polysiloxanes (PQMS) with different compositions were synthesized by hydrolytic polycondensation and subsequent quaternization. Then, a series of antibacterial polyurethane copolymers (PQMS–PU) with PQMS and PPG as soft segments were prepared by two-step condensation methods. GPC, FTIR and 1H-NMR were employed to analyze the chemical structural and composition. The surface migrations of polysiloxane segment tethered QAS groups and the distribution of N+ on the surface were quantitatively characterized by XPS. The microphase morphology and wettability properties of the copolymer films were investigated by AFM, TEM and dynamic contact angle tests. The migration of the biocide groups to the surface caused by the microphase separation between polysiloxane soft segments and hard segments was determined. The quantitative relationships of the polysiloxane segments and QAS group distribution on the surface with the wettability and antibacterial activity of the copolymer films were demonstrated. Within the designed range, the obtained copolymers exhibited very low surface free energy and excellent antibacterial activity towards Escherichia coli, which was of great environmental friendliness and industrial interest for textile and marine coating application.
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