Synthesis, Surface Properties, and Antibacterial Activity of Novel Ester-Containing Cationic Silicone Surfactants and Their Utilization as Fabric-Finishing Agents

Article abstract of DOI:10.1002/jsde.12211

In this study, a series of cationic silicone surfactants SiQC_nCl containing ester groups and double long-chain alkyls (n = 9, 11, 13, 15, and 17) were synthesized by microwave irradiation and characterized using infrared Fourier transform (FTIR), ¹H nuclear magnetic resonance (¹H NMR), and thermogravimetric analysis (TGA). Surface activity and adsorption of these surfactants were investigated by measuring the equilibrium surface tension. The critical micelle concentration (CMC) decreased with increasing alkyl length of SiQC_nCl at 25 °C and so did the corresponding surface tension at the CMC (γ_CMC). The aggregation behavior in aqueous solutions was also investigated systemically through transmission electron microscopy (TEM) and dynamic light scattering (DLS). Spherical or ellipsoidal-like aggregates with diameters ranging from 300 to 900 nm were observed. It is also shown that the cationic silicone surfactants exhibit certain antibacterial properties against Staphylococcus aureus but slightly poor to Escherichia coli. The morphological structure of SiQC₁₅Cl-treated cotton fabrics was observed using scanning electron microscopy (SEM), which showed that the surface became neat and smooth. What is more, the finished cotton fabrics maintained some antibacterial properties with improved softness, which may provide a more comfortable and healthy lifestyle. This work may also be helpful to the design and application of functional cationic silicone surfactants.