Material Characterization

Responsible: prof. Laura E. Depero

To enhance the understanding of materials properties and behavior is the primary aim of Chem4Tech. In particular, the activities are focused to develop and to optimize experimental techniques, methods, and protocols for studying new materials/devices.

Researches cover a very wide variety of materials (metal, ceramic, glass, semiconductor, polymers, and bio-organic materials) and they are carried out in collaboration with several national and international researchers belonging to government as well as private research laboratories.

Several facilities are available at Chem4Tech for physical, chemical, functional, and mechanical characterization of materials.

X-ray powder diffraction is most widely used for the identification of unknown crystalline materials (e.g. minerals, inorganic compounds).X-ray powder diffraction (XRD) is a rapid analytical technique primarily used for phase identification of a crystalline material and can provide information on unit cell dimensions. The analyzed material is finely ground, homogenized, and average bulk composition is determined.

KEY FEATURES:

• Measure conditions: Room conditions. Non-desctructive analysis.

• Materials: Powders, solids, thick films

• Measured properties: Crystalline phases identification. Unit cell dimensions.

Glancing Incidence X-ray diffraction technique is employed for thin films characterisation, as it is surface sensitive. Specular reflectivity (XRR) can characterize films in the range of 1nm to about 1000 nm in thickness depending on the material. It provides accurate measurement of thin film thickness, density and the interface width between layers.

Non-specular scattering measurements yield information about layer interface, and it is possible to the difference between surface roughness and layer interdiffusion. Commercially available simulation packages are used for the modelling and understanding of specular and non-specular scattering data.

D8 Discover instrument is built with a modular design by combining high performance components. The main components are:

• Sources: Available anode materials: Cu and Cr; TWIST-TUBE system for fast and easy switching between line and spot focus

• Detectors:VÅNTEC-500- Two-dimensional (2-D) detector for X-ray diffraction, based on Bruker AXS’ proprietary MIKROGAPTM technology. It has a huge detector window of 140 mm diameter and a capability of collecting images with both high count rate and excellent resolution.

• Sample stages: Compact cradle - 3-axis cradle with motorized Chi- and Phi-rotations and a manual Z translation. The large Chi-range and unlimited Phi-range enable straightforward texture measurements, whereas residual stress measurements can be made in both omega- and psi-mode (iso-inclination and side-inclination respectively). A clamp holder is optionally available for mounting irregular bulk samples.

The 883 Basic IC plus allows the determination of anions, cations or polar substances in various matrices.

It is ideal for routine applications in water analysis, the food branch and the chemical industry.

The S2 PICOFOX TXRF spectrometer is a versatile instrument for trace element analysis of different kinds of samples. It is completely independend of any cooling media and therefore applicable for on-site analysis. Further benefits of the S2 PICOFOX are the simple calibration routine, the absence of matrix or memory effects and the ability for fast multi-element analysis.

The main difference with respect to common XRF-spectrometers is the use of monochromatic radiation and the total reflection optic. Illuminating the sample with a totally reflected beam reduces the absorption as well as the scattering of the beam in the sample and its matrix. Resulting benefits are a largely reduced background noise, and consequently much higher sensitivities andthe significantly reduction of matrix effects.In general all elements starting from Sodium up to Uranium (excl. Niobium, Molybdenum and Technetium) can be analyzed by the S2 PICOFOX. Quantitative analysis is based on internal standardization. Therefore, an element, which is not present in the sample, must be added for quantification.

Sample type and preparation:

• Liquids can be preparated directly on the sample tray. An amount of several μl is transferred to the glass disc using a pipette and subsequently evaporated in a desiccator or drying oven.

  • For solid samples different kinds of preparation are possible: -Powdered samples (suspended matter, soils, minerals, metals, pigments, biogenous solids etc.) can be analyzed directly after preparation of the material on the sample tray. Typically, a few μg of sample material are transferred, using a Q-tip or a lint-free tissue. - In a similar way the direct preparation of single microsamples (particles, slivers etc.) is possible. - Alternatively, powdered solids can be prepared as a suspension with volatile solvents like acetone or methanol. The suspension is then pipetted onto the sample tray.

• SMART STORE system

The LabRam HR system provides ultra high spectroscopic resolution and a unique wavelength range capability that provides both great flexibility and high performance.

It is a an integrated, simple to use , and high stability benchtop instrument designed to undertake reproducible Raman measurements at high, medium or even low spectral resolution. The high resolution mode is uniquely ideal for subtle band analysis such as that for phase (crystalline/amorphous), of proteins, hydrogen and weak bonding forces and semiconductor stress measurements infact most applications where it is important for the precise characterisation of position or shape of the Raman spectral features. Band analysis in the order of 0.3cm-1 to 1cm-1 is particularly suited to the HR mode. Its dual capabilities also enable more routine Raman analysis and even broader band laser induced micro-fluorescence or luminescence to be conducted all upon the same benchtop instrument.

• • Unique high, medium and low resolution multichannel spectral modes.

  • Suitable for Raman, fluorescence and luminescence measurements.

  • True confocality - maximum spatial resolution and better defined images.

  • Multiple laser capability, from visible to near IR (specially extended NIR and UVversions).

  • Ultimate stability.

  • Large 1024 pixel CCD chip dimensions - various chip formats are available.

  • Unique adjustable angle notch filter technology.

  • Automated software operation including external cooling stages.

  • Expandable configuration (second exit port ,additional detection options, FSM microscope).

The QE65000 has a Hamamatsu back-thinned detector with great response in the UV. Its 2D arrangement of pixels (1044 horizontal x 64 vertical) is responsive from 200-1100 nm. The specific range and resolution are determined by your grating and entrance slit selections. The detector’s columns are binned, or summed, inside the detector prior to the readout process, thereby minimizing readout noise. The detector can be cooled down to -20.0 ºC with the onboard TE-cooler to reduce dark noise. The reduction of noise and dark signal allows integration times of the spectrometer of up to 15 minutes, which greatly enhances the detection limit in low-light level applications. The combination of the spectrometer’s low-noise detector and 16-bit A/D Converter delivers a dynamic range of 25000:1 and a signal-to-noise ratio of >1000:1.

The QE65000 is a great option for low-light level applications including fluorescence, Raman spectroscopy, DNA sequencing, astronomy and thin-film reflectivity. You can set the integration time of the spectrometer (analogous to the shutter speed of a camera) from 7 milliseconds to 10 minutes, with virtually no spectral distortion.

The CM-2600d includesa d/8° sphere, Numerical Gloss-Control (NGC) and, now available for the first time in a portable instrument, numerical UV-Control (NUVC). Together with the high energy xenon flash illumination and the high resolution monolithic dual beam monochromator, the entire optical system is free from moving parts and therefore guarantees substantial advantages in raggedness and reliability. The Numerical Gloss Control (NGC) which, for each measurement, provides simultaneous data with specular component included (SCI) and excluded (SCE). Instead of mechanical moving parts, NGC sequentially fires two xenon flashes (one including UV and one excluding UV energy), for SCI and SCE. At any time, you can show both measurement results in the display of the CM-2600d. The advantages of NGC technology lies in its superior optical results as well as the absence of any moving parts making the CM-2600d rugged enough for portable applications.

Two measuring apertures to cover all sample sizes The CM-2600d offers great flexibility of use with two interchangeable measurement apertures with Ø 8 mm (MAV) and Ø 3 mm (SAV). Changing the aperture mask is very easy and quick. The two lens position settings guarantee perfect data correlation with both apertures. These two apertures enable to measure samples of all size and shapes and avoid taking time consuming average measurements on structured surfaces or faulty results on small samples.

The MZ16 A is the world’s first and only fully motorized stereomicroscope. It is an automated stereomicroscope workstation for inspection and digital imaging; all components of which can be controlled via PC.

The MZ16 A’s digital display offers a clear readout of user-calibrated total magnification and field of view at every zoom position which allows for ‘spot-on’ repeat inspection and saves valuable time in documenting optical information.

User-defined point-to-point measurements are available at the ‘touch of a button’ using the MZ16 A and its calibrated graticule.

Scanning probe microscopy (SPM) is a generic term for a group of techniques that scan a fine probe (or tip) over a surface, either very close to the surface or just touching it, constantly or intermittently. The tip is moved using very sensitive piezoelectric elements with such precision that atomic resolution can be achieved in many of the operating modes. The operation modes can be divided into two principal technique groups – Scanning Tunnelling Microscopy (STM) and Atomic Force Microscopy (AFM). STM requires conductive samples and generates images with atomic resolution showing how the tunnelling current changes with distance between the tip and the sample. A number of spectroscopic methods are also associated with this technique. AFM works also on non-conductive samples and measures the interatomic attractive or repulsive forces. With AFM it is generally harder to achieve atomic resolution. There is a large number of derived techniques that are able to measure the mechanical, electrical, magnetic and chemical properties of surfaces. The environmental SPM can examine samples under "real world" conditions. Standard AFM modes include contact, friction force microscopy, current image, non-contact and discrete contact with either slope detection or frequency detection, and phase imaging.

Microwave digestion is a common technique used to dissolve heavy metals in the presence of organic matrices prior to analysis by spectroscopic techniques. This technique is usually performed by exposing the sample to a strong acid in a closed vessel and raising the temperature and pressure through microwave irradiation and thus the sample matrix is decomposed.

Discover SP-D is a pressurized mineralizer microwave able to treat samples in a simple and extremely fast way. Discover SP-D is able to ineralize samples in just 10 minutes, cooling time included!! All this by using 10 or 35 ml containers, provided with a quick-closing cap. The main use of the Discover SP-D is in the field of metals analysis.

Thermal treatments in furnaces can be perfomed up to 1600°C.

An environmental test chamber is also available for tests in the range of –20° to 80° C and with controlled humidity up to 95%.

An innovative method obtained with a rapid, dynamic solid – liquid extractor is proposed for extraction. A process in which the actual pressure applied to the water varies cyclically in a range between 0 and 10 bar has been applied. The process is performed at room temperature, and the energy cost is primarily due to the liquid pressure. An extractive cycle, includes a static and a dynamic phase. The figure shows the frontal (a) and rear (b) view of Naviglio extractor instrument equipped with 2L chamber.

The extraction with Naviglio Extractor is faster, easier and complete with respect to maceration process. From an economical point of view this instrument is cheaper and requires a minimum consumption of energy compared to extraction by other techniques such as supercritical fluids (SFE) or to the Extractor Accelerated Solvent Extraction (ASE). Moreover, it permits recovery of the extractable substances at ambient operating temperatures, it is a reproducible process, which may be used to obtain standardized extracts for pharmacological applications. The above mentioned advantages guarantee the production of high quality extracts. Extractor is successfully applied in the pharmacology, especially in field of officinal plants. Indeed, the extracts obtained utilizing Extractor instrument contain a quantity of active principles higher than those from industrial extraction technique.

Cantisens® by Concentris GmbH (Basel, Swiss) is an analytical instrument for highly sensitive detection of molecules and fast and reliable measurement of molecular interactions. The instrument takes advantage of the high sensitivity of microfabricated cantilevers. Microcantilevers (MCs) are micromechanical oscillators free at one end with length of few hundreds of mm, width of tens of microns and thickness of several mm. In particular arrays of 8 silicon MCs (500 mm long, 100 mm wide and 1 mm thick) are used for this instrumentation. MC surface is coated (functionalized) to bind the molecular probe able to selectively interact with the target molecules. For example when a gas or a liquid containing the target molecules comes into contact with the sensor surface, the MC will respond mechanically to this chemical binding process. Surface stress due to electrostatic repulsion or steric effects leads to a bending of the cantilever (static sensor). Additionally, the mass increase caused by the bound target molecules results in a decrease of the cantilever’s resonance frequency (dynamic sensor). Both effects are measured optically by determining the position of the laser beam reflected by the cantilever surface. The instrument allows not only a sensitive detection of a given target, but also a quantitative analysis, since the cantilever bending and the resonance frequency shift are correlated with the number of adsorbed molecules. By applying the appropriate chemical layer on microcantilevers, Cantisens® can be used for medical diagnostics, drug discovery, process quality, environmental analysis, security devices or calorimetry.

KEY FEATURES:

• Eight channel parallel sensing: parallel measurement of the behaviour of arrays of eight cantilevers;

• Equipment for measurements in static mode;

• Label free detection of molecules;

• Low volume (5µl) fluid measurement cell;

• Integrated temperature control with a stability of 0.01 °C until 90 °C;

• Automatic fluid handling system.

KSV's CAM 200 is a fully computer controlled instrument based on video capture of images and automatic image analysis for measuring static or dynamic contact angles, surface or interfacial tensions of liquids, surface free energies, and absorption of liquids into porous materials.