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Shared Research Facilities
In addition to the high quality scientific equipment of the Department’s Research Laboratories, which is used by the respective Laboratory personnel and collaborating research groups, the Department has a number of instruments that is available to support the research activities of all of its members. Access to this equipment is obtained by contacting the faculty member who is responsible for the operation of each apparatus.
X-RAY DIFFRACTOMETER (XRD)
Model Siemens D-5000 with a Bragg-Brentano configuration, equipped with a Cu source (λ=1.5415 Å).
The X-ray diffractograms of crystalline compounds are obtained by measuring the intensity of monochromatic X-ray radiation that is diffracted by a crystal into many specific directions. The present diffractometer uses the Bragg-Brentano configuration, in which the sample is stationary while the X-ray tube and the detector are rotated around. The diffractograms obtained allow the identification of crystalline inorganic and organic compounds (pure or in mixtures), the calculation of basic parameters of the crystal lattice (Rietveld analysis), the estimation of the degree of crystallization, etc.
The research areas which are supported by the diffractometer include those related to the synthesis of new materials and electronic materials, catalysis, metallurgy and associated processes (erosion, formation of alloys), crystallization processes (in physiology, technology, environment), coating processes, building materials and materials for the maintenance of cultural heritage, etc.
FIELD EMISSION-ENVIRONMENTAL SCANNING ELECTRON MICROSCOPE (FE-ESEM)
FEI QUANTA 250 FEG, able to operate at high pressures (10-4000 Pa).
The FE-ESEM is a valuable tool for the morphological characterization of both inorganic and organic materials at scales of the order of a few nanometers. The instrument enables imaging and analysis of conductive, non-conductive and/or hydrated specimens in high and low vacuum. The microscope produces images of a sample by scanning it with a focused beam of electrons, which interact with atoms in the specimen and produce signals that contain information about the sample’s topography and composition. The FE-SEM produces clearer and less electrostatically distorted images, compared to conventional SEM. The method allows the investigation of material characteristics such as texture and morphology as a function of the synthesis conditions employed. The simultaneous microanalysis (semi-quantitative or quantitative) of samples provides valuable information in the fields of materials characterization, diagnostic failures of materials or even the identification of specific characteristics which can explain the behavior of materials in different circumstances. Almost all research areas related to materials benefit from ESEM analyzes .
The Departments’ FE- ESEM has been purchased through LIMMAT, a Swiss non-profit foundation, with the financial support of a donor.
ULTRAVIOLET-VISIBLE (UV-VIS) SPECTROPHOTOMETER
Perkin-Elmer λ-35 (190-1100 nm), equipped with an integrating sphere for Diffuse Reflectance Spectroscopic (DRS) studies. Suitable for solid, liquid, paste and powdered samples.
A high resolution instrument that is suitable for the quantitative analysis of anions and cations in solution. It enables the development of analytical methods by means of scanning a wide range of wavelengths. The ability to obtain diffuse reflectance spectra (DRS) provides a useful tool for the characterization of polycrystalline materials such as catalysts and catalyst substrates, the investigation of the optical properties of glasses and colloidal suspensions as well as for analyses in food chemistry, pharmaceuticals, textiles, etc.
DIFFERENTIAL SCANNING CALORIMETER (DSC)
The instrument measures the difference in the amount of heat required to increase the temperature of a sample and a reference material of known heat capacity as a function of temperature. In this way it enables carrying out mechanistic studies related to the formation of new phases, crystallization of melts, melting of solids, etc. A particular advantage of the present instrument is the temperature range of operation (up to 1500oC), which allows the characterization of various materials such as ceramics, metal alloys, catalyst substrates, pharmaceuticals, biological materials (mainly hard tissues), food, cosmetics, etc.
THERMOGRAVIMETRIC ANALYSER (TGA)
ΤΑ Q50 (1000⁰C)
This general purpose thermogravimetric analyser is used to record the mass loss (or gain) of solid samples as a function of temperature.
The measured weight changes characterize both the specific material and the processes that take place upon heating. Common applications of TGA include the study of ceramics, catalysts, minerals and composites, pharmaceuticals, food etc.
(Sigma 70, KSV). for static and dynamic measurements.
The tensiometer is used to measure the surface or interfacial tension of liquids by Du-Nouy ring or Wilhelmy Plate methods.
It provides important information on the properties of solutions of organic compounds (surfactants), the behavior of water-soluble polymers (micellization concentrations), the complexation of polymers, the composition of pharmaceutical products etc.
ATOMIC ABSORPTION SPECTROMETER (AAS)
Perkin –Elmer AAnalyst 300, equipped with a graphite furnace
A basic analytical instrument that is used for the quantitative determination of chemical elements in liquid samples at ppb levels (solids are generally converted into a solution by an appropriate dissolution methods). The sample is vaporized in an electrothermal atomizer (graphite tube) and then irradiated by an element-specific light source. The atoms absorb ultraviolet or visible light and make transitions to higher electronic energy levels. The analyte concentration is determined from a calibration curve generated with the use of standards of known concentration. The instrument supports many research fields in the Department, ranging from materials synthesis to qualitative characterization of natural and potable waters.
An analytical instrument that is used to study the infrared absorption characteristics of the fundamental vibrations of chemical groups. These characteristic absorptions allow the identification of chemical groups and contribute to the qualitative and quantitative determination of compounds, especially organic compounds and polymers. The apparatus is used to obtain information in synthesis processes and chemical transformations.
SURFACE AREA AND PORE SIZE DISTRIBUTION ANALYZER
The apparatus is suitable for measuring the specific surface area of solid samples as well as their total porosity (0.5-500 Å) and pore size distribution. Measurements are performed in a series of experiments that involve absorption-desorption of nitrogen/helium mixtures at the temperature of liquid nitrogen (absorption) and at room temperature (desorption). It is a valuable instrument for the characterization of catalysts, crystalline and amorphous powders, absorbents, building materials, etc.