In this work, we report a fast and efficient in-situ growth method of Zinc-Oxide nanowires (ZnO-NWs) and the real-time monitoring of NW growth over wide microfluidic chambers. The ZnO-NW hydrothermal synthesis is carried out in dynamic mode involving a continuous flow of the growth solution inside the microfluidic chamber. The biomimetic flow distribution tree is designed as input and output stages for the chamber to ensure uniform distribution of growth solution flow aiming to produce uniform NWs on the wide chamber. The real time monitoring is achieved by continuous acquisition of UV-vis spectra of the ZnO-NWs during the growth, which is achieved for the first time to the best of the author’s knowledge.
In this work, we report fast and efficient synthesis of ZnO-NWs in-situ within microfluidic chamber taking all the advantages of microfluidic devices. The growth done in dynamic mode involving flow of the growth solution inside the microchamber. Well-oriented ZnO-NWs are achieved in just 8-16 minutes in dynamic mode having similar properties to the synthesized NWs in 2-3 hours growth time using the static method. The morphology and optical properties of the ZnONWs characterized using SEM and UV-Vis spectroscopy. This method opens the door for fast, cheap and localized growth of NWs to be used within microfluidics platforms.
In this work, we propose a simple and time-saving method for the characterization of the ZnO-NWs. The method is based on the measurement of the spectral reflection of the ZnO-NWs in the UV-VIS-NIR ranges. Then the ZnO-NWs effective refractive index, and subsequently the density, and the length are obtained making use of the interference pattern contrast and periodicity in the reflection response versus wavelength. The extracted NWs length and density using the proposed method show good agreement with the SEM results. This characterization method opens the door for easy and cheap monitoring of the growth within microfluidic environment.
We have studied polluting gases in tobacco smoke by investigating the phenomenon of capturing and photocatalysis effects of ZnO nanowire array (NWA). Capturing and photocatalysis reactions were continuously tracked by FTIR spectroscopy. The presence of ZnO improves the capture rate at room temperature, while the photocatalytic reactions can lead to a further reduction of the pollutants. MEMS-FTIR spectrometer operating in the Mid-Infra-Red appeared as a very promising tool for the online monitoring of air purification process.