Paola Gallo Stampino

Associate Professor of Materials Science, Department of Chemistry, Materials and Chemical Engineering "G. Natta", Polytechnic University of Milan

Paola Gallo Stampino graduated in Materials Science from the University of Milan-Bicocca with a thesis entitled "Synthesis via sol-gel, spectromagnetic characterization and luminescence properties of scintillating glasses". In 2007, she obtained a PhD in Materials Engineering from the Polytechnic University of Milan, defending a thesis entitled: "Reactivity and hydration kinetics processes in cementitious systems: stabilization/solidification of hazardous wastes".

From May 2003 to February 2004, he served as a research fellow at the Polytechnic University of Milan (Department of Chemistry, Materials and Chemical Engineering "Giulio Natta") collaborating on a project entitled: "Mechanisms of surface interaction in mineral phases: immobilization of hazardous waste in cementitious matrices".

From March 2004 to February 2007, he attended the XIX cycle doctoral school in "Materials Engineering" with a project entitled "Surface reactivity and hydration kinetics in processes for the immobilization of organic pollutants in cementitious materials".

From March 2007 to June 2007, he served as a fellow at the Polytechnic of Milan (Department of Chemistry, Materials and Chemical Engineering "Giulio Natta") collaborating on a project in collaboration with INSTM entitled: "Characterization of materials for polymer electrolyte membrane fuel cells (PEM)".

From July 2007 to April 2008, he worked on a project in collaboration between the Politecnico di Milano (Department of Chemistry, Materials and Chemical Engineering "Giulio Natta") and the company Seal S.p.a. titled "New Materials for Polymer Fuel Cells (PEM)". Since May 2008, he has been a researcher at the Department of Chemistry, Materials, and Chemical Engineering.

Scientific Activity
The scientific activity has been focused on various themes mainly concerning materials for the environment and energy, as evidenced by the results published in international scientific journals and proceedings of national and international conferences (30 articles in international journals, 40 contributions to national and international conferences).

Research Activity Collaborates with Prof. Giovanni Dotelli at the laboratory of "Materials for the environment and energy" of the Department of Chemistry, Materials and Chemical Engineering of the Polytechnic University of Milan since May 2003. Over the years, he has coordinated various experimental activities in the laboratory, supervising first and second level thesis students and PhD students. He has participated in research projects funded by the Ministry of Scientific Research (PRIN) and by the Cariplo Foundation.

Research activity description
In the field of environmental materials, attention was initially focused on waste immobilization technologies using cement-based materials, leveraging a series of studies on the hydration processes of cementitious materials. Research in the clay materials sector started from a well-known problem in the adsorbent materials sector, which is the disposal of liquid organic waste, as immobilization techniques in cement matrices, currently the best system for solidification/stabilization of hazardous waste, are not effective without the use of an adsorbent material.

A possible solution to the problem is indeed represented by the use of adsorbent materials compatible with the cementitious matrix. For this purpose, both commercial organophilic clays and clays prepared ad hoc have been used, and adsorption tests of various pollutants have been carried out on both. The different chemical nature of the organic molecules used as a test has also allowed for an interesting study of the adsorption mechanisms.

Starting from these research experiences, interest has shifted towards the study of organic-inorganic hybrid materials based on natural clays. Clays modified with non-ionic surfactants of edible grade (PEG) have been prepared. In the most recent works, the amount of modifier inserted into the clay material has been controlled by appropriately managing the operational parameters of the intercalation process.

These materials, commonly called modified clays or organoclays, are used in many sectors: from adsorbent materials for the removal of pollutants from water or for the immobilization of waste destined for solidification in a cementitious matrix to nanocomposites with a polymer matrix. The properties of these hybrid materials have recently been recognized as of high interest in the field of controlled drug release. The use of biocompatible and food-grade organic materials, such as PEG, is specifically aimed at this type of applications.

I am currently studying new types of nano-tubular clay materials, halloysites, for which biocompatibility has been demonstrated. In the field of materials for energy, research activity is focused in particular on materials for polymer electrolyte membrane fuel cells (PEMFC). Current research on these devices is aimed at improving efficiency, reducing costs, and decreasing weight. The performance of a fuel cell depends heavily on the quality of its components, especially on the characteristics of the materials used. Therefore, studying the individual components and developing materials capable of optimizing the performance of the final device is of paramount importance.

Specifically, research in this sector has focused on a component, namely the Gas Diffusion Layer, which performs numerous functions, including transporting gaseous reactants from the channels of the bipolar plates to the electrodes, removing water produced, transporting the heat generated by the reaction, and finally providing mechanical support to the membrane inside the cell. The research activity, started in collaboration with an Italian company that produces the carbon fiber-based fabric that constitutes the GDL, has been mainly focused on the surface treatment of the initial fabric. Initially, attention was paid to hydrophobization treatments using conventional fluorinated polymers such as PTFE, and in recent years alternative fluorinated polymers to PTFE have also been considered, which have allowed to achieve higher electrical performance.

In parallel, the study focused on the preparation methodology of inks for the deposition of a microporous layer (MPL) that serves different functions, including improving the electrical contact between the various components inside the cell and promoting the diffusion of reagents and products. In particular, in the first part of the work, different ink preparation methodologies to be used for coating were compared; the effects of different operational variables on the rheological behavior of the inks under examination were studied, such as the method and time of mixing, conducting reproducibility, stability, and scale-up studies on the prepared inks.

In the preparation of these microporous layers, "innovative" formulations were considered compared to literature data, using materials such as nanotubes within the formulations and using viscosity-modulating agents, such as carboxymethylcellulose.