Polymer Membrane Modified with Photocatalytic and Plasmonic Nanoparticles for Self-Cleaning Filters

Abstract

In this study, we developed a filtering material for facial masks, which is capable of trapping and subsequent inactivation of bacteria under white light emitting diodes (LED) or sunlight irradiation. Such a functionality is achieved via the modification of the composite membrane based on porous polymer with photocatalytic (TiO2) and plasmonic (Ag) nanoparticles. The porous polymer is produced by means of a computer numerical control machine, which rolls a photoresist/thermoplastic mixture into a ~20-µm-thick membrane followed by its thermal/ultraviolet (UV) hardening and porosification. TiO2 nanoparticles are prepared by hydrothermal and sol-gel techniques. Colloidal synthesis is utilized to fabricate Ag nanoparticles. The TiO2 photocatalytic activity under UV excitation as well as a photothermal effect generated by plasmonic Ag nanoparticles subjected to LED irradiation are studied by the assessment of methylene blue (MB) decomposition. We demonstrate that, in contrast to the filter of the standard facial medical mask, the polymer membrane modified with spray-coated TiO2 and Ag nanoparticles prevents the penetration of bacillus subtilis from its top to bottom side and significantly inhibits bacterial growth when exposed to LED or sunlight.

Improvement of Heat Dissipation in Ag/Ni Substrates for Testing Cu-TiO2/TiO2-Modified Filters Using SERS Spectroscopy

“…The fabrication of the polymer membrane and its modification with photocatalytically active particles followed a slightly modified procedure previously reported [22]. Cu-doped TiO 2 nanoparticles were inserted in the spraying suspension instead of the silver ones.…”

“…Cu-doped TiO 2 nanoparticles were inserted in the spraying suspension instead of the silver ones. The Sol-gel method was selected to prepare the TiO 2 -based nanoparticles since it resulted in fabrication of the powder with higher photocatalytic activity [22], and this approach is generally more attractive for large-scale TiO 2 production.…”

“…The other relevant goal is to decrease the pore sizes in the mask filter for improved prevention of the nanoobject entry into the upper respiratory organs as well as to ensure sufficient air flow density for the user's breathing. For example, in a previous study [22], we proposed the fabrication of polymer membrane with nanosized pores coated with silver and titanium dioxide nanostructures for filtering out nanoobjects of 100 nm diameter accompanied by the deactivation of bacteria upon external light exposure. An ability to stop passing organic contaminations was proved in the SERS spectroscopy study of the air pumped via the developed membrane.…”

Density functional theory for doped TiO2: current research strategies and advancements

“…Besides, the TiO 2 properties can be modelled ahead by conducting laborious experiments upon engineering various TiO 2 structures as doped or defected TiO 2 , heterostructures, or doped and defected TiO 2 heterostructures to screen the outcome of these combinations. TiO 2 also displays antibacterial properties closely linked to its photocatalytic response when exposed to UV light [44][45][46][47][48]. Under the UV illumination, TiO 2 generates reactive oxygen species, such as hydroxyl radicals and superoxide ions.…”

Silver Nanoparticles’ Localized Surface Plasmon Resonances Emerged in Polymeric Environments: Theory and Experiment

“…The goal of this combination is to obtain novel materials and devices with enhanced functionality and responsiveness [21][22][23]. The synergistic effects of these hybrid nanostructured materials can be leveraged in functional systems, endowing them with remarkable optoelectronic, sensing, catalytic, and antibacterial properties, as well as improved light harvesting efficiency [17,18,[24][25][26][27][28]. These attributes render these materials highly versatile and suitable for applications in diverse fields.…”