The secrets of porous materials
José Pichel Andrés/DICYT Scientists from the University of Aveiro are studying the properties of porous materials. The progress being achieved by researchers in this field takes the form of increasingly lighter and smaller materials with more properties. This work can be a starting point for the development of new devices that are applied in the field of electronics, for example.
Porous materials are “those with a structural geometry that produces cavities between the atoms that form it”, DiCYT was told by Paula Ferreira, a scientist of the Research Centre for Ceramic Materials and Compounds (Centro de Investigação em Materiais Cerâmicos e Compósitos, CICECO). These cavities are called pores. According to their dimensions, the materials that form them are classified as microporous, mesoporous, and macroporous according to the International Union of Pure and Applied Chemistry (IUPAC).
Porosity gives materials important properties, such as low density meaning a light weight, and a large surface area to store molecules in the pores. Moreover, the pore size can act as a sieve to separate molecules. “Porous materials may act as catalyst hosts or as vehicles for transporting drugs and carrying out a controlled release of specific molecules”, the researcher points out. Porosity is also useful for modifying the intrinsic properties of materials.
To be precise, Paula Ferreira's research group is developing porous materials in various shapes and compositions that are designed for different applications. “We produce hybrid porous materials in which we integrate organic molecules with silicon oxide for capturing and separating gases”, she comments, together with “heterogeneous catalysis and the adsorption of pollutants in water”.
Porosity allows the creation of lighter materials and the introduction of materials with different properties into the pores. This means that the same physical dimension can be multi-functional and means that increasingly smaller designs are possible.
The scientists of the University of Aveiro have been working in this area of research for 18 years and are currently concentrating on two projects. One of these is the designing of materials capable of separating methane from carbon dioxide in biogas to subsequently reduce the CO2 or transform it into useful molecules.
Reducing the size of electronic devices
The second is the development of materials with electrical and magnetic properties in such a way that faced with a magnetic stimulus they provide an electrical response and vice versa. “These materials are extremely important for reducing the size of electronic devices and will provide a new generation of memories for storing data”, the expert declares.
In order to carry out this type of research, the CICECO uses chemical synthesis techniques that are relatively cheap. For example, when creating porosity in materials this team of scientists uses relatively large molecules that can subsequently be extracted or burnt, thus producing the cavities.
In this manner “we have increased our knowledge, in particular our understanding of how porosity and the chemical nature of materials affect their final properties”. These achievements are often reflected by the main scientific journals in the field. The final objective is to convert these advances into practical applications; in order to do so work is being carried out on improving the materials to make them increasingly efficient.