As the potential adverse health and environmental effects
of nanoscale
pollutants have garnered significant attention, the demand for monitoring
and capturing ultrafine particulate matter has been growing. With
the rise in ultrafine dust emissions, this issue has become increasingly
important. However, submicron particles require advanced strategies
to be captured because of their limited inertial effect. For example,
electrostatic air filters have been investigated for their improved
performance in the fine particle regime. On the other hand, Raman
spectroscopy was proposed as a promising analytical strategy for aerosol
particles because it can be used to conveniently detect analytes in
a label-free manner. Thus, the synergistic integration of these strategies
can open new applications for addressing environment-related challenges.
This study presents a multifunctional approach for achieving both
air filtration and surface-enhanced Raman scattering (SERS) for analyte
identification. We propose a nanoporous membrane composed of a thin
gold layer, copper, and copper oxide to provide the desired functions.
The structures are produced by performing scalable electrodeposition
and subsequent electron-beam evaporation, attaining an excellent filtration
efficiency of 95.9% with an applied voltage of 5 kV for 300 nm KCl
particles and a pressure drop of 121 Pa. Raman intensity measurements
confirm that the nanodendritic surface of the membrane intensifies
the Raman signals and allows for the detection of 10 μL of nanoplastic
particle dispersion with a concentration of 50 μg/mL. Rhodamine
6G aerosol stream with an approximate particle deposition rate of
0.040 × 106 mm–2·min–1 is also identified in a minimum detectable time of 50 s. The membrane
is shown to be recyclable owing to its structural robustness in organic
solvents. In addition, the fatigue resistance of the structure is
evaluated through 22,000 iterative loading cycles at a pressure of
177 kPa. No performance degradation is observed after the fatigue
loading.