UV-exposure (pH) wearable sensors based on photochromic materials incorporated in flexible substrates - Postdoctoral Porject Nov 2020 - Nov 2021

#Nanophotoncs, #Solid-State, #biodiesel production, #photocatalysts, #nanoclusters

The objective of this project focuses on the development of novel ultraviolet (UV) radiation sensors based on inorganic materials with reversible photochromic properties (hackmanites, perovskites), incorporated into a flexible nanocellulose patch (wearable technology). The development of reversible photo-chromic sensors aims to strengthen the basic science project carried out at the Optics Research Centre (CIO), under the direction of Dr. Eduardo Coutiño González, by creating a synergy between the research lines of inorganic photonic materials and biophotonic nanosensors, to promote the development of a platform of sensing devices that have a direct impact on the proposal of preventive solutions to public health problems. Therefore, the goals of the project are :
- To generate useful knowledge to develop new reversible photochromic materials from inorganic materials such as hackmanites and perovskites.
- To generate a portfolio of functional materials with potential application in the proposal of solutions to problems such as those caused by overexposure of the skin or perishable foods to UV radiation, by designing flexible sensors that allow rapid and accurate measurement of ultraviolet radiation. Another of the project's objectives is based on the development of protocols for the synthesis of the photochromic materials to be used in the project, as well as structural and physicochemical characterisation studies.

Apart from my main project on the elaboration of photochromic materials, I collaborate in other research projects on metal nanoclusters (Ni²⁺, Cu²⁺, Zn²⁺, etc.) in zeolites, through photoreduction for photoluminescent materials. On the other hand, I collaborate in the project of photocatalysis and photolysis with catalysts for the study of the absorption of carbon dioxide. I am currently collaborating in the writing of an article on lithium metasilicate for environmental purposes.
Another of my new responsibilities (where it is totally new to me), is to be responsible for the research activities of three undergraduate students. Two chemistry students from the University of Guanajuato and one materials engineering student from the Technological University of Tulancingo. These stays are virtual, due to the current health crisis of Sars-Cov2. The topics we are developing are reviews in :

• Photochromic, organic and inorganic materials.
• Thermal and atmospheric effects on inorganic photoluminescent materials.
• Inorganic materials with optoelectronic properties.

When I arrived at a recently created research group, I had the opportunity to collaborate in the administration of the management of the laboratory in the inventory of equipment and reagents, the implementation of security measures for the different members of the different laboratories, as well as having a first experience in the development of the group's website ( Nanophotonics & Functional Materials and the management) of their social networks (Twitter and LinkedIn).

Effect of nanocrystallinity on homogeneous and heterogeneous growth of cobalt magnetic super crystals - PhD Thesis 2016 - 2019

#Nanocrystals, #EffectOfNanocrystallinity, #ReverseMicelles, #LigandExchange, #ExchangeBias, #Supercrystals

Abstract:
Metallic nanocrystals 3D self-organization (NCx) is a new generation of nanostructured materials, called supercrystals. They present a new collective property, which allows them to be involved in different technological applications. In this thesis, we propose a comparative study concerning heterogeneous and homogeneous growth in the absence or presence of a magnetic field, of cobalt nanocrystals, obtained by the micellar route (7.5 nm, 11%, fcc type) and by the dismutation of an organometallic salt ([CoCl(PPh₃)₃]) (9 nm, 10%, hc type). The former are passivated with dodecanoic acid and the latter with oleylamine. By controlling the amount of oleylamine in Co-hc NCx colloidal solution and the volume of solution deposited, we promote the growth of super crystals, relatively similar to those obtained with Co-fcc NCx. A new method of ligand exchange (from oleylamine to dodecanoic acid) is proposed, promoting Co-hc NCx whose interaction with dodecanoic acid is covalent. The deposits conducted with these NCx promote for the first time colloidal crystals of Co-hc NCx passivated with dodecanoic acid. Using a solution oxidation method, core/shell nanocrystals [Co (ferromagnetic)@ CoO (antiferromagnetic)] of uniform size were obtained with a monocrystalline metal core (hc) and an fcc shell. Preliminary studies of magnetic properties show magnetic exchange coupling at the ferromagnetic/antiferromagnetic interface.

TEM - Cobalt nanoparticles (9 nm 9%), SEM of supercristals of cobalt NCs tetradecane/oleylamine (9:1) organometallic synthesys, SEM-FEG of supercristals of cobalt NCs organometallic synthesys (100% oleylamine)

Apart from carrying out my thesis project, Sorbonne Université, as part of the doctoral formation, encouraged us to take different formations in different fields, for my part I had doctoral formations in:

• Introduction to Management
• Teamwork
• Time management
• Management against stress (sophrology)
• Conflict resolution
• Economic intelligence

Communications

2019 - Poster - Colloids Conferences, Sitges, Barcelona, Spain.

2019 - Scientific Seminar - Foundation Deutsch de la Meurthe, Cité International Universitaire de Paris, France

2019 - Scientific Seminar - Collège d’Espagne, Cité International Universitaire de Paris, France

2019 - Scientific Seminar - Doc Day MONARIS – Paris, France

2018 - Scientific Seminar - Danish Foundation, Cité International Universitaire de Paris, France

2017 - Scientific Seminar - Foundation Maison de Mexique, Cité International Universitaire de Paris, France

2017 - Scientific Seminar - Doc Day SPHYNXS / SPEC / CEA – Saclay, France

Synthesis of Cs_xNa_yW₃ based electrochromic thin films for sunlight filtration - Research Engineer 2015 - 2016

#TungstenOxide, #ShlenkLine, #AssemblyOfSynthesisSystems

My first objective was to obtain a FRIA-FNRS funding to do a PhD in materials science in the GreenMat research group, in which I had a strong preparation to master the topic and present to a jury in only 5 minutes and 10 minutes of questions. The proposed PhD topic was the development of sodium (Na) and caesium (Cs) doped tungsten oxide nanocrystals "tungsten bronzes", as well as being functionalised with niobium oxide polyoxometals. With the aim of developing smart windows, using the Ultrasonic Spray Pyrolysis technique for the deposition of conductive thin films.
As I did not obtain the funding, my objective was to set up a part of the laboratory for the synthesis of the nanocrystals using a Schlenk line. I was responsible for coordinating the cleaning, setting up the line, contacting the material suppliers for temperature control. Although I was not able to make an experimental development, I gained a lot of experience in managing a project.

During my period at the University of Liège, I had the opportunity to attend courses in the fundamentals of crystallography, fundamentals of scanning electron microscopy, transmission electron microscopy, as well as taking a course in computer operation and introduction to C++.

Synthesis of oxysulfide nanoparticles of controlled morphology and composition - Master 2 Internship Jan 2015 - Jul 2015

#MetalOxysulfide, #InertAtmosphere, #XRD, #TEM, #SchlenkLine

The research project during my master internship at LCMCP, was the development of metal oxysulfides (M₂O₂S) at a nanometric scale from the literature of microscopic metal oxysulfides. The synthesis was carried out in a Schlenk line, where the effects of the composition for the development of oxysulfides were studied, modifying stoichiometric quantities, the use of different solvents, metal precursors or surfactants, as well as the times required to obtain nanoparticles or nanoplatelets, in addition to studying the effects of different reaction temperatures. The metal oxysulfides (M₂O₂S) studied were: Gd, Sm, Co, Bi, In, Ti, V, as well as GdIn.

In the image you can see some of the modifications made during the synthesis of the metal oxysulfides, either with excess sulfur, without the use of surfactants, as well as the modification of the reaction temperature, giving hexagonal nanoplatelets. This master project allowed me to have a first experience in handling syntheses on a Schlenk line in inert atmospheres (argon), to improve my French writing and to lose the fear of presenting my results to a scientific audience. I thank my advisor, Dr Sophie Carenco, for her patience throughout my stay, for all her knowledge on the subject, as well as on other topics that I still try to apply constantly.

Synthesis of gold nanoparticles by sonochemistry - Bachelor's Thesis 2013 - 2014

#GoldNanoparticles, #Sonochemistry

My undergraduate thesis was developed between two laboratories. The synthesis of gold nanoparticles via sonochemistry was carried out at the Centro Conjunto de Investigaciones en Quimica Sustentable (CCIQS) and the characterization of the materials at the Laboratorio Nacional de la Universidad de Guanajuato. The synthesis was carried out by using an acid precursor of gold, together with DMSA, where the latter would serve as a reductant and surfactant. Reaction times, reaction temperatures and the type of sonication to be used (intermittent or continuous) were studied. Due to the poor results obtained with DMSA as reductant, it was decided to reduce the gold precursor with NaBH4 at different concentrations. The sizes of gold nanoparticles were around 60 nm in the form of rods. To stabilize the nanoparticles in a stable suspension, they were tested at pH 9 to avoid agglomerations between them for several weeks.

The characterization of the nanomaterials was carried out at the national laboratory of the University of Guanajuato, using STEM and DLS to determine the size of nanoparticles. On the other hand, IR spectroscopy was used to determine if the DMSA was anchored to the surface of the gold nanoparticles. On the other hand, UV-Vis studies were performed to identify the plasmon positioning of the nanoparticles obtained.

Absorption of phosphates, sulphates, nitrates from snowmelt salts in stormwater from Lake Saint-Martin, Quebec, Canada - Bachelor's Internship 2013

#AnalitycalChemistry, #WaterEngineering, #Quebec, #AscorbicMethod

This research internship at the water engineering department of the University of Laval was an excellent opportunity for me to go deeper into analytical chemistry. The project, headed by Pr. Rosa Galvez (currently a senator), aims at the adsorption of sulfates, nitrates and phosphates from the Saint-Martin lake using porous stones as well as certain plants of the region, caused by the de-icing salts used during the intense winters in the Quebec region.

The activities of my internship was carried out in two parts, on the one hand, the sampling around the lake in the rainwater intakes, where the first data were taken. The samples were taken to the laboratory, where different stages of filtration were carried out, to carry out UV-Vis studies by the ascorbic acid method and to determine the concentrations of phosphates, sulfates and nitrates.

Studies of physical-chemical effects on the Gas Diffusion Layer of hydrogene Fuel Cells - Bacherlor's Internship 2012

#FuelCells, #Hydrogen, #Oxygen, #Electrochemistry, #GasDiffusinLayer, #PlatinumNanoparticles

The work performed in this research internship was carried out in an institute of energy applications (ITAE - CNR). My research project was to analyze the different stability conditions that the gas diffusion layer (GLD) can present before oxygen and hydrogen reach the fuel cell membrane. Using platinum nanoparticles embedded in carbon in the gas diffusion layer. To impregnate these materials, a spray deposition system was used manually as well as automatically.

Synthesis of cobalt-ferrite nanoparticles for hyperthermia characterisation - Bachelor's Internship 2011

#MagneticNanoparticles, #Hyperthermia, #XRD, #IR, #UV, #GoldNanoparticles, #Sonochemistry

This project was intended as a first contact with nanosciences. The stay was short, only two months, and the objective was to synthesise cobalt ferrite nanoparticles by thermal decomposition, which were characterised by IR, UV, TEM and hyperthermia. What I learned from this project was to have a better understanding of colloidal solutions, the first steps in having patience for bad results, the understanding of the graphs obtained from the characterisations.