Publications by authors named "Julian Parra-Barranco"
Article Synopsis
- The study focuses on enhancing the wetting behavior of surfaces, which is crucial for applications like microfluidics and self-cleaning technologies.
- Researchers discovered that a specific kind of elastomer, PDMS, can create well-ordered surface patterns when coated with nanostructured titanium oxide and mechanically deformed, contrasting typical wrinkled patterns.
- This process allows for reversible modification of the surfaces, enabling control over droplet movement and capture based on their properties, thanks to a unique dual-scale roughness and alignment of grooves created during deformation.
Article Synopsis
- - Researchers investigated how UV irradiation can preactivate TiO2 and ITO surfaces, improving the absorption of organic molecules through low-pressure evaporation.
- - The deposition of organic molecules on these oxides was monitored using various techniques (SEM, UV-vis, XRD, RBS, and photoluminescence spectroscopy) to study the resulting patterns of organic nanowires.
- - The study also utilized X-ray photoelectron spectroscopy and molecular dynamics simulations to clarify the mechanisms of enhanced adsorption, and examined the creation of hybrid organic/inorganic semiconductors via controlled sublimation on mesoporous TiO2.
ITO thin films have been prepared by electron beam evaporation at oblique angles (OA), directly and while assisting their growth with a downstream plasma. The films microstructure, characterized by scanning electron microscopy, atomic force microscopy, and glancing incidence small-angle X-ray scattering, consisted of tilted and separated nanostructures. In the plasma assisted films, the tilting angle decreased and the nanocolumns became associated in the form of bundles along the direction perpendicular to the flux of evaporated material.
View Article and Find Full Text PDFWe present a straightforward procedure of self-surface patterning with potential applications as large area gratings, invisible labeling, optomechanical transducers, or smart windows. The methodology is based in the formation of parallel micrometric crack patterns when polydimethylsiloxane foils coated with tilted nanocolumnar SiO2 thin films are manually bent. The SiO2 thin films are grown by glancing angle deposition at room temperature.
View Article and Find Full Text PDFPorous Bragg microcavities formed by stacking a series of porous nanocolumnar layers with alternate low (SiO2) and high (TiO2) refractive index materials have been prepared by physical vapor deposition at glancing angles (GLAD). By strictly controlling the porosity and refractive index of the individual films, as well as the relative orientation of the nanocolumns from one layer to the next, very porous and nondispersive high optical quality microcavities have been manufactured. These photonic structures have been implemented into responsive devices to characterize liquids, mixtures of liquids, or solutions flowing through them.
View Article and Find Full Text PDFArticle Synopsis
- This paper presents a detailed analysis of GLAD TiO(2) thin films using techniques like atomic force microscopy and GISAXS to study their microstructure and porosity.
- The research emphasizes that the deposition angle and film thickness significantly influence the film's properties, especially regarding nanocolumn structures.
- The findings also underline the relevance of porosity and specific dimensions in evaluating the optical properties of these films for applications like antireflective coatings and composite material development.