Facile fabrication of plasmonic wettability contrast paper surface for droplet array-based SERS sensing

Optically trapped SiO2@Au particle-dye hybrid-based SERS detection of Hg2+ ions

“…Owing to the electrostatic interaction, the mercury ion interacts with plasmonic Au nanoparticles to create amalgam and thus affect the plasmonic oscillations. [44][45][46] The variation in the plasmonic field affects the Raman signal of a probe molecule. Herein, 100 µM of Rhodamine 6G is used as the probe molecule, and a 3-rectangular chamber is used in which the incubated particle is optically trapped.…”

Oil-Grafted Track-Assisted Directional Transport of Water Droplets and Submerged Air Bubbles on Solid Surfaces

“…An air bubble approaching the smooth surface experiences a hydrodynamic repulsive force originating from the drainage of the liquid film beneath the air bubble, which can be understood based on Reynolds lubrication theory and the augmented Young-Laplace equation explained elsewhere. 41−45 Under the situation wherein the thickness of the drainage liquid film is less than the micrometer scale, the surface forces (disjoining pressure originating from various surface components such as van der Waals, electrostatic double layer, and hydrophobic interactions) also contribute toward the force balancing with the Laplace pressure of the air bubble ( = P R 2 , where R is the radius of the bubble) to create stable adhesion of the air bubble. The largest air bubble that can be stably adhered to the silicone oil-grafted substrate is measured to be 49 μL, which corresponds to an adhesion force of 92 μN.…”

“…Tailoring of the surface wettability properties via physical as well as chemical methods is a subject of intense research as it finds applications in diverse areas, ranging from superhydrophobic textiles to therapeutic delivery. − The majority of these surfaces are fabricated by biomimicking naturally occurring animals or plants. For example, the surface of lotus leaves is mimicked to achieve superhydrophobic surfaces whereas desert beetle and pitcher plant surfaces are imitated to obtain wettability contrast and slippery surfaces, respectively. − Advances in the fabrication of hierarchical micro and nanoscale structures facilitated the creation of surfaces with extreme wettability, ranging from superhydrophobic to superhydrophilic surfaces. − Inspired by the fog-basking nature of the desert beetle, research has been carried out to create a wettability contrast surface that can harvest water from fog and humidity.…”

Superhydrophilic/Superhydrophobic Droplet Microarrays of Low Surface Tension Biofluids for Nucleic Acid Detection

“…Nevertheless, some bioassays employ biofluids with properties that differ greatly from water, especially surface tension, viscosity, and adsorption capabilities. [33] Peethan et al [34] studied the effect of surface tension of a CTAB (cetyl trimethyl ammonium bromide) solution on droplet splitting to a droplet microarray on a candle-soot-coated patterned SHL/SHB surface. The surface tension of the solution varied from 61 to 38.5 mN m −1 with varying concentrations of CTAB, and the authors found that the droplet is still splitting into arrays and the daughter droplet volume remains nearly the same.…”