Initiating the Photopolymerization Behaviors of Water-Soluble Polymerizable Polysiloxane-Polyether Block Imidazolium Ionic Liquids with Antibacterial Capability

Three water-soluble polymerizable polysiloxane-polyether block imidazolium ionic liquids containing alpha-hydroxy alkylphenone groups ([Si-E-n-2959Im-A][TsO] (n = 1, 3, 5) are designed and synthesized as novel green photoinitiators. The photochemical properties and photoinitiation mechanism of the [Si-E-n-2959Im-A][TsO] are investigated by ultraviolet absorption spectroscopy, real-time infrared spectroscopy and electron spin resonance. [Si-E-n-2959Im-A][TsO] exhibit good water solubility that reaches up to 12%. [Si-E-n-2959Im-A][TsO] not only show desirable thermal properties and low saturated vapor pressure, but also effectively initiate photopolymerization. The initial weight loss of [Si-E-n-2959Im-A][TsO] (n = 1, 3, 5) is at 256 degrees C and their saturated vapor pressures are less than 3.0 Pa. The migration of the photolysis fragments of [Si-E-n-2959Im-A][TsO] from the cured material is mitigated significantly by their polymerizability and high molecular weights. Furthermore, biological tests involving Escherichia coli and Staphylococcus aureus strains in contact with the UV-cured films initiated by [Si-E-n-2959Im-A][TsO] demonstrate that [Si-E-n-2959Im-A][TsO] are effective antibacterial agents. Therefore, [Si-E-n-2959Im-A][TsO] are promising components for the preparation of environmentally friendly materials and antibacterial coatings.