Mawin Martinez Jimenez

District University of Bogotá | UDISTRITAL · Facultad del Medio Ambiente

Gold nanoparticles (AuNPs) are commonly synthesized using the citrate reduction method, reducing Au3+ into Au1+ ions and facilitating the disproportionation of aurous species to Au atoms (Au0). This method results on citrate-capped AuNPs with valence single states Au0. Here, we report a methodology that allows obtaining AuNPs by the dewetting proce...

The present study investigates the high-temperature oxidation behaviour of nanostructure surface layered AISI 304L stainless steel. A severely deformed layer of ∼300 μm thickness, consisting of nanoscale grains (∼40 nm size) in the topmost region, is successfully developed using the surface mechanical attrition treatment (SMAT) process. The SMATed...

Intrinsic self-healing materials have received significant attention due to the characteristic recovery after damage properties through reversible dynamic covalent and non-covalent interactions. Furthermore, functional recovery with reliable mechanical properties are highly keen as protective coatings, specifically for devices and sensors vulnerabl...

Heavy metal pollution is posing a severe health risk on living organisms. Therefore, significant research efforts are focused on their detection. Here, we developed a sensing platform sensor for the selective detection of lead(II) acetate. The sensor is based on self-assembled polyethyleneimine-functionalized carbon nanotubes (PEI-CNTs) and graphen...

Self-healing coatings as thin films have been widely exploited in the last decade due to the conformational ability to adhere practically at any surface, bringing multiple regenerations in damaged areas. Poly(ethylene imine) (PEI) and poly(acrylic acid) (PAA) are the most used polyelectrolytes to grow self-healing layer-by-layer films; however, few...

The vast, unexplored chemical realm of multi-principal element alloys (MPEAs) has encouraged researchers to design and synthetize advanced materials based on refractory metals, metalloids, and deoxidizer elements, that are expected to follow single-phase, solid solution high-entropy alloys (HEAs)’ footsteps. In this paper, we have theoretically and...

Nanostructured CrN thin films are obtained by combining RF physical vapor and dynamic glancing angle deposition using a computer-controlled substrate oscillatory motion. By using an appropriate frequency for substrate oscillation, it becomes feasible to tailor the physical properties of thin films deposited onto the substrate. The films are deposit...

The CrN films were grown by rf-magnetron sputtering using a dynamic glancing angle deposition technique. In this technique, the substrate oscillates in front of the sputtering target with an angular amplitude and frequency commanded by a Programmable Logic Controller. The purpose of this paper is to study the physical properties of the CrN coatings...

Reduced graphene oxide (rGO) layers are known to be significantly conductive along the basal plane throughout delocalized sp² domains. Defects present in rGO implies in disordered systems with numerous localized sites, resulting in a charge transport governed mainly by a 2D variable range hopping (VRH) mechanism. These characteristics are observed...

The unique electronic, mechanical and optical properties of graphene make it a remarkable 2D material, widely explored in a plethora of applications. However, graphene zero-band gap and the production of defect-free pristine graphene in large areas still limit some applications. To circumvent these issues, graphene-derived 2D materials have arisen...

Graphene is a breakthrough 2D material due to its unique mechanical, electrical, and thermal properties, with considerable responsiveness in real applications. However, the coverage of large areas with pristine graphene is a challenge and graphene derivatives have been alternatively exploited to produce hybrid and composite materials that allow for...

Precision agriculture is crucial for increasing food output without expanding the cultivable area, which requires sensors to be deployed for controlling the level of nutrients in the soil. In this paper, we report on a microfluidic electronic tongue (e-tongue) based on impedance measurements which is capable of distinguishing soil samples enriched...