MATERICA

A flame burning in controlled condition can be considered as a chemical reactor system is meant for the gas phase synthesis of nano materials. The basic principle is to produce a flame by burning a suitable fuel with an oxidizer: by acting on the flame parameters (fuel/oxidizer ratio, typology of fuels…) and/or introducing a precursor in the oxidizing flame, is it possible to obtain carbonaceous materials and/or nanocrystalline oxides with specific chemico-physical features.

Carbon black is largely constituted of hydrophobic material organized, at nanoscale level, in graphene layers with various degree of deviation from planarity and a different amount of less organized areas (i.e., amorphous and disordered carbons) that makes carbon black particles more reactive than graphite. Carbon black is a versatile carbonaceous material prone to be structurally and chemically modified in quite mild conditions.

Carbon Capture and Storage (CCS) embodies a group of technologies consisting in the separation of CO2, one of the main responsible for the greenhouse effect, from large industrial and energy related sources, transport to a storage location and long-term isolation from the atmosphere. CCS through CO2 adsorption with solid sorbents is one of the most promising options for post – combustion CO2 capture strategies. Magnetic iron oxide (magnetite) particles are good low-cost CO2 sorbents. Carbon black coated with magnetite allows reducing agglomeration of magnetite particles, thus enhancing the CO2 capture performances and application in technologically advanced systems.

The picture shows blocks of graphene-like material obtained from carbon black using an alternative procedure compared to the classic one which involves the use of graphite as a starting material. This low-cost approach is highly compatible to an industrial scale-up process with a particular attention to the environmental impact since all procedures are performed in aqueous environments.

Thanks to their good stability in water, driven by residuals oxygen functional groups, graphene-like layers obtained from carbon black appear as a very versatile nanomaterial, suitable for the preparation in aqueous environment of composites with tunable chemical/physical properties such as microporosity, conductivity, catalytic performances and biocompatibility. The picture shows graphene/iron oxide magnetic hybrids obtained combining graphene-like layers and iron salts.

The metal organic frameworks (MOFs) are new generation crystalline materials. The MOFs typical feature is the high surface area (comparable or greater than zeolites, microporous crystalline volcanic minerals) and a porosity highly tunable, which makes them excellent adsorbers of gas and water. One of the most striking characteristics of some MOFs is the gradual color change as a result of absorption of water of the atmosphere. The picture captures the change of color, from blue to cerulean blue, of a copper-based MOF, after exposure to the air.

A copper-based metal organic frameworks (MOF) was combined with graphene to obtain a hybrid material which, unlike the pure MOF, is conductive. The hybrid can be obtained with a variable amount of graphene in order to modulate the porosity and electrical characteristics. These new hybrid materials open up significant prospects in the field of sensoristic and CO₂ capture strategies. The presence of copper gives a distinctive blue color to the hybrid.

Polyvinylpyrrolidone (PVP) is a water-soluble polymer made from the monomer N-vinylpyrrolidone. In specific controlled conditions PVP forms a stable gold-yellow gel containing up to 80% of its weight in water. PVP gel is soft and biocompatible, finding application as component of transdermal drug delivery systems. PVP acts as antinucleating agents that retard the crystallization of a drug improving the solubility of a drug in the matrix.

The polymer polivinilpirrolidone (PVP) is soluble in water and other polar solvents and is highly compatible with water-stable graphene-like (GL) layers obtained from carbon black. Under specific controlled conditions PVP and GL forms black stable soft gel containing up to 80% of its weight in water. Thanks to the biocompatibility and to the partial hydrophobic character of the GL layers, the PVP/GL gel finds application as component of transdermal drug delivery systems for non-polar drugs.

Dialysis is a common laboratory technique that allows separating, by means of a semipermeable membrane, large molecules or particles from small impurities. Sometimes, however, you may manifest fascinating phenomena when the membrane, immersed in water, is kept at low temperatures to avoid the growth of mold. The picture shows a curious phenomenon of formation of air channels after the unexpected freezing of a dialysis membrane containing a suspension of graphene to be purified.

Infrared spectroscopy deals with the infrared region of the electromagnetic spectrum, that is light with a longer wavelength and lower frequency than visible light. As with all spectroscopic techniques, it is a fundamental tool to study solid surfaces. Solid samples can be prepared in a variety of ways. One common method is to grind a quantity of the sample with a specially purified salt (usually potassium bromide) finely. This powder mixture is then pressed in a mechanical press to form a translucent pellet through which the beam of the spectrometer can pass.

Elemental analysis is a process where a sample is analyzed for its elemental composition. Elemental analysis falls within the ambit of analytical chemistry, the set of instruments involved in deciphering the chemical nature of our world.

The most common form of elemental analysis, CHN (Carbon, hydrogen and nitrogen) analysis, is accomplished by combustion analysis in suitable packed columns. In this technique, a sample is burned in an excess of oxygen and various traps collect the combustion products (carbon dioxide, water, and nitric oxide). The masses of these combustion products are used to calculate the composition of the unknown sample.