The IV PhD degree and PhD special prize award ceremony will take place on November 24, 2017.
Jose Muñoz's thesis, entitled "Advanced amperometric nanocomposite sensors based on carbon nanotubes and graphene: characterization, optimization, functionalization and applications", was supervised by Dr. María del Mar Baeza and Dr. Francisco Déspedes, from the Sensors and Biosensors group (Chemistry Department, UAB).
His PhD research focused on the synthesis of (bio)sensors formed by polymers and carbon nanotubes or graphene. These carbon-based materials increase the conductivity of the insulating polymers, and so, their analytical properties change.
About the thesis
Among the wide range of nanocomposites, the incorporation of conducting nanostructured carbon materials, such as carbon nanotubes (CNTs) and graphene, into an insulating polymeric matrix is a very attractive way to combine the unique mechanical and electrical properties of individual filler with the advantages of plastics.
Concretely, carbon–based nanocomposite materials have played a leading role in the analytical electrochemistry field, particularly in (bio)sensor devices, due to their interesting advantages regarding to a pure conductive material, such as versatility, durability, easy surface regeneration and integration, facile incorporation of a variety of (bio)modifiers or low background current, among others. Accordingly, this thesis tackles the development of advanced amperometric nanocomposite sensors that having been optimized regarding to carbon/polymer composition ratios, can be tunable with different types of nanoparticles (NPs) for improving their electroanalytical efficiency.
The electrical properties of these nanocomposites and, therefore, their analytical applicability, are directly influenced by the conducting particles nature and the amount and spatial distribution of them through the insulating polymeric matrix. One of the most important electrochemical properties of these materials is the similarity of their electrochemical behavior with a microelectrode array. Thus, an optimization of the carbon/polymer ratio with respect to the nature of the conducting material will allow to achieve a greater dispersion of the conducting areas through the non-conducting areas, presenting similar benefits to the microelectrode array.
In addition, it is known that some parameters, such as composite resistivity, heterogeneous electron transfer rate, material robustness and background capacitance current are strongly influenced by the physical nature of the raw CNT sample, such as their diameter/length ratio and purity, fact that may strongly influences the final electroanalytical response of the transducer material. Under this context, the first step of this thesis consisted of implementing a group of instrumental techniques that, systematically applied, have allowed the characterization and optimization of nanocomposite materials composition based on CNTs and epoxy resin (Epotek H77) in relation to the nature of the raw CNT sample for the fabrication of more efficient electrochemical sensors. The developed characterization protocol includes electrical, electrochemical, morphological, microscopic, spectroscopic and electroanalytical tools.
Having been optimized the MWCNT/epoxy composition ratios, the next step consisted of enhancing the analytical performance of these electrochemical nanocomposite sensors introducing some electrocatalytical effect by the incorporation of different NPs. For this goal, a simple methodology for synthesizing a wide range of different NPs has been developed. Intermatrix Synthesis (IMS) has been used as a green technique to design three different routes for CNT/epoxy nanocomposite electrodes modification, which offer a customized way for the preparation of sensitive amperometric sensors. Finally, the characterization and functionalization studies applied for CNT–based electrochemical nanocomposite sensors have been extended for nanocomposite materials based on another allotropic form of carbon: the graphene, which is the last discovery in terms of nanostructured carbon material.
About the PhD special prize award ceremony
With 66 PhD programmes, the UAB is one of the leading Catalan universities in the production of theses and generates approximately a third of the doctoral theses that are defended in the Catalan university system each year.
With the PhD degree and PhD special prize award ceremonies, which are held twice during the academic year (around May and November), the UAB demonstrates its appreciation for the effort and dedication of young researchers and their contribution to the generation of knowledge. The event is organized by the School for Doctoral Studies and the UAB Alumni.
The main value of the UAB is its human capital and the new doctors are an essential element for the continuation of excellent lines of research. That excellence is based on the quality of the PhDs as a distinctive indicator.
The PhD special prizes confer value to theses which have received the qualification of excellence "Cum Laude" and which, having been proposed by the Admissions Committee of each academic programme, stand out for their contribution and advance in the different areas of our University. The prizes are awarded per academic year, in accordance with PhD regulations and with the criteria specified in each PhD programme.