ABSTRACT
Recently, considerable attention has been drawn to the field of micro/nanofluidic channels. However, current methods for fabricating micro/nanochannels are complex, costly, and time-intensive. In the present work, we successfully fabricated transparent submicron-channels on fused silica substrates (SiO2) using a straightforward laser process. To achieve this, a single-pulse excimer laser irradiation in a rear side configuration was employed to treat a thin film of UV-absorbing silicon suboxide (SiOx) through the transparent SiO2 substrate. A polydimethylsiloxane (PDMS) superstrate (coating layer) was applied over the SiOx film before laser exposure, serving as a confinement for controlled structure formation induced by the laser. Under optimal laser fluence, the thin SiOx film buckled, leading to the formation of channels with a width ranging from 10 to 20 µm and a height of 800 to 1200 nm, exhibiting a bell-like cross-sections following the so-called Euler buckling mode. Wider channels displayed morphologies resembling varicose or telephone cord modes. Subsequent high-temperature annealing led to the oxidation of SiOx, resulting transparent SiO2 channels on the fused silica substrate. The manufactured nanochannels exhibited promising potential for effectively transporting fluids of diverse viscosities. Various fluids were conveyed through these nanochannels via capillary action and in accordance with the Lucas-Washburn equation.
ABSTRACT
In recent years, the combination of factors such as growing population and global climate change has resulted in freshwater shortages. Therefore, water harvesting from the atmospheric fog in order to produce freshwater supply inspired by nature has received much attention. The water harvesting capability of the creatures is significantly based on the combination of both wettability states on their surfaces. In this study, a facile physicochemical hybrid method was used for the fabrication of glass surfaces with contrast wettability. First, fractal and regular repeated geometric patterns were deposited on a glass substrate using brass sheet as donor material by laser induced forward transfer (LIFT) method. Subsequently, stearic acid (SA) treatment was used to convert the wettability of the superhydrophilic (SHL) deposited patterns on glass to superhydrophobic. In order to investigate the effect of the shape of designed patterns on glass surfaces in the water harvesting efficiency, the amount of collected water for a period of time from untreated hydrophilic (HL) glass, superhydrophobic (SHB) glass and hybrid superhydrophobic/hydrophilic (SHB-HL) surfaces were measured. The obtained results indicate that the hybrid of superhydrophobic and hydrophilic regions and selecting the optimal pattern can improve the water harvesting performance by up to 300%.
Subject(s)
Lasers , Water , Hydrophobic and Hydrophilic Interactions , Surface Properties , Water/chemistry , WettabilityABSTRACT
In this work, nanoporous carbon (NPC) was synthesized by direct carbonization of MOF-5 (a famous metal-organic framework). The structure and morphology of the prepared MOF-derived nanoporous carbon (MOF-NPC) were investigated by X-ray diffraction, N2 adsorption/desorption isotherm, Raman spectroscopy, thermogravimetric analysis, and scanning electron microscopy methods. The MOF-NPC was then used to adsorb copper ions from aqueous solutions. To evaluate the performance of the prepared MOF-NPC to remove copper ions, both adsorption kinetics and adsorption equilibrium experiments were carried out and then the obtained data were modeled with various models. Also, the efficacy of temperature and the pH of the solution on the removal efficiency were checked. The results show that the prepared MOF-NPC is a superadsorbent for the removal of copper ions from aqueous solutions. Finally, the removal percentage of copper ions by the prepared MOF-NPC was compared with other activated carbon adsorbents to show its incredible efficiency.
