Sofroniou Constantina, Scacchi Alberto, Le Huyen, Espinosa Rodriguez Edgar, D'Agosto Franck, Lansalot Muriel, Dunlop Patrick S M, Ternan Nigel G, Martín-Fabiani Ignacio
Department of Materials, Loughborough University, Loughborough LE11 3TU, United Kingdom.
Department of Applied Physics, Aalto University, P.O. Box 11000, Aalto FI-00076, Finland.
ACS Appl Polym Mater. 2024 Aug 23;6(17):10298-10310. doi: 10.1021/acsapm.4c01436. eCollection 2024 Sep 13.
In this study, evaporation-induced size segregation and interparticle interactions are harnessed to tune the microstructure of photocatalytic colloidal coatings containing TiO nanoparticles and polymer particles. This enabled the fabrication of a library of five distinct microstructures: TiO-on-top stratification, a thin top layer of polymer or TiO, homogeneous films of raspberry particles, and a sandwich structure. The photocatalytic and antibacterial activities of the coatings were evaluated by testing the viability of Methicillin-resistant (MRSA) bacteria using the ISO-27447 protocol, showing a strong correlation with the microstructure. UVA irradiation for 4 h induces a reduction in MRSA viability in all coating systems, ranging from 0.6 to 1.1 log. Films with TiO-enriched top surfaces exhibit better resistance to prolonged exposure to disinfection and bacterial testing. The remaining systems, nonetheless, present higher antibacterial activity because of a larger number of pores and coating defects that enhance light and water accessibility for the generation and transport of reactive oxygen species. This work establishes design rules for photocatalytic coatings based on the interplay between performance and film architecture, offering valuable insights for several applications, including antibacterial surfaces, self-cleaning/antifogging applications, and water purification.
在本研究中，利用蒸发诱导的尺寸分离和颗粒间相互作用来调控含有TiO纳米颗粒和聚合物颗粒的光催化胶体涂层的微观结构。这使得能够制备出包含五种不同微观结构的涂层库：TiO顶层分层结构、聚合物或TiO的薄顶层、覆盆子颗粒均匀膜以及三明治结构。通过使用ISO - 27447协议测试耐甲氧西林金黄色葡萄球菌（MRSA）细菌的活力来评估涂层的光催化和抗菌活性，结果表明其与微观结构有很强的相关性。4小时的紫外线照射会使所有涂层体系中的MRSA活力降低，降低幅度在0.6至1.1个对数单位之间。具有富含TiO顶层表面的薄膜对长时间的消毒和细菌测试表现出更好的抗性。然而，其余体系由于大量的孔隙和涂层缺陷，提高了活性氧生成和传输所需的光和水的可及性，因而具有更高的抗菌活性。这项工作基于性能与薄膜结构之间的相互作用建立了光催化涂层的设计规则，为包括抗菌表面、自清洁/防雾应用以及水净化在内的多种应用提供了有价值的见解。
