Scanning Electron Microscopy (SEM) is a technique applied to the characterization of materials. This technique allows the observation and characterization of the morphology of a sample, showing details of the surface up to the nanometric scale.

With this technique, we can observe the detailed morphology of the surface, as well as perform a dimensional analysis of the sample, measure its roughness, particle sizes, and determine the prefered location of elements in the sample (elemental mapping), among others.

Our benchtop SEM-EDS is equipped with:

BSED Detector (Backscatter Electron Detector) – Provides high contrast in the image (areas of the sample with higher atomic number elements appear clearer in the image) and allows the analysis of non-conductive samples in their natural state (without coating);

EDS Detector – Secondary electron detector that provides more detailed surface and topographic information by detecting the electrons diffused inelastically through the material

Maximum magnification: 150000x;

Resolution up to 17 nm (sample dependent).

APPLICATION EXAMPLES

Study of the dispersion efficiency of microcapsules in tissues

Determination of the elemental composition of electronic contacts

Obtaining the particle size profile and composition of milk powder samples

Characterization of tablet coatings

Characterization of small metallic fragments in order to determine their origin

Determination of the elemental composition of ore

X-Ray Fluorescence (XRF) is a non-destructive analytical technique used to determine the elemental chemical composition of all types of materials except gases. For this reason it is the method of choice for many different types of applications, particularly in quality control of materials and industrial production. The XRF technique is excellent for both qualitative and quantitative analysis.

The technique is subdivided into two categories: Energy Dispersive XRF and Wavelength Dispersive XRF (ED-XRF and WD-XRF, respectively). The difference between the two lies in the signal processing and detection. In the ED-XRF technique, the X-ray photons emitted by the sample are all detected simultaneously, usually by a solid-state semiconductor detector, while in WD-XRF the X-rays are diffracted by a crystal to be separated into their wavelengths and then detected. The ED-XRF technique is usually faster and the equipment is simpler and easier to use. WD-XRF equipment is usually larger, more complex and slower to measure, but can detect more elements (up to Beryllium), with better resolution and lower detection limits.

APPLICATION EXAMPLES

Quantification of Silicon in textile fibers

Verification of possible contaminations in flours resulting from milling

Elemental quantification of liquid paints

Elementary quantification of phosphoric rocks

Detection of defective auto parts

Quantification of chlorides remaining from the synthesis of new APIs

Laser Diffraction is an experimental analysis technique that allows determining sizes and size distribution of particles in a range of a few nanometers to a few millimeters. A quantitative size distribution of the entire population of particles is obtained in order to determine which diameters represent a certain percentage of that population. The distribution can be in number or, more usually, in volume.

The theoretical models that allow the calculation of particle diameters are Fraunhofer’s and Mie’s. According to ISO 13320-1, Fraunhofer theory gives good results for particle sizes above 50 microns. For smaller sizes, in general, Mie’s theory is more appropriate. Mie’s theory is more complete and correct because it considers a certain degree of transparency of the particle to the laser, however this implies prior knowledge of the optical properties of the sample, namely its Refractive Index (RI) and Absorption Index (AI). Laser diffraction has proven useful for the following industries: environmental, ceramics, pharmaceutical, food and cosmetics.

The determination of particle size and distribution by the laser diffraction technique is recognized by numerous standards and standardization agencies including: ISO, ASTM and USP.

APPLICATION EXAMPLES

Characterization of the evolution of the particle size profile of nano structures in the different synthesis steps

Characterization of polyurethane suspensions

Characterization of ashes resulting from forest fires

Determination of the particle size profiles of the different cosmetic components

Determination of particle size profiles of different paint components

Characterization of milk – NIZO index – Particle size distribution

Characterization of API

Support in the development of new formulations

Differential Scanning Calorimetry (DSC) is one of the most widely used techniques in the thermal characterization of materials. In this technique, the heat flow between the sample and a reference is monitored when subjected to a controlled temperature program, which changes whenever there is a phenomenon in the sample that consumes or releases energy. These phenomena may be of a physical or chemical nature. Physical transformations include melting, crystallization, vaporization, and glass transitions, among others. On the other hand, chemical transformations involve reactions that can be decomposition, combustion, chemical absorption, polymerization, solid-solid transitions, among others.

The DSC technique allows not only to determine the temperature at which a given endo/exothermal phenomenon occurs, but also to determine the amount of energy (enthalpy) involved in it. In addition to this type of information, the technique also allows one to measure heat capacity values of a material in accordance with ASTM E 1269, ISO 11357-4 and DIN 51007 standards, as well as determine degrees of purity or perform kinetic studies.

APPLICATION EXAMPLES

Determination of API freeze-drying conditions

Determination of the specific heat in rubber

Determination of the constituent polymers of a product

Verification of the curing process in resins

Verification of thermal coatings on fabrics

Determination of crystallinity of polymeric products

Determination of polymer composition in electrical cable sheathing

Determination of oxidation time

Thermogravimetry is a Thermal Analysis technique where the loss or gain in mass of a sample when subjected to a controlled temperature program is monitored. The changes in mass can be due to chemical processes, such as decomposition reactions with gas release or combustion reactions, and physical processes, such as vaporization of volatiles or absorption of moisture, among others. The combination of this technique with others such as DSC or analysis of the gases released (FTIR, MS, GC-MS) allows a more concrete identification of the phenomena and allows inferences about the reaction mechanism. This fact, together with the mass loss associated with the phenomenon, enables the quantification of the different components that constitute the sample.

APPLICATION EXAMPLES

Determination of the decomposition temperature of API

Determination of the percentages of the constituent elements

Determination of the residual mass of liquid paints

Verification of the composition of ceramic pastes

Dynamic Light Scattering (DLS) is a technique that is commonly used to measure particle size and can estimate the distribution of submicrometer particles in scattering. DLS analyzes the hydrodynamic mobility of the particles. The success of the technique is mainly based on the fact that it provides estimates of the average particle size and size distribution within a few minutes.

Electrophoretic light scattering (ELS) is an indirect analysis of measuring electrophoretic mobility through the Doppler shift observed in light scattered by particles. In an ELS experiment, a beam of coherent light is focused on particles dispersed in a liquid and subjected to an electric field. The charged particles move toward either the anode or the cathode, depending on the sign of their charge on the medium. ELS provides fast, accurate, automatic, and highly reproducible electrophorograms of complex particles dispersed in aqueous or non-aqueous media, without the need to use standard particles for calibration.

The mathematical models for correlogram analysis are the cumulant method for size and polydispersity; and the non-negative least squares method for size distribution. The Zeta potential is derived from the electrophoretic mobility using the Henry function, which can be approximated by the Smoluchowski equation or Hückel equation according to the relative thickness of the electrical double layer.

APPLICATION EXAMPLES

Stability of pigments

Stability of polyurethane solutions

Average nanoparticle size

Stability over time of solutions

X-Ray Diffraction is a very versatile technique with broad application in the characterization of materials, since it allows to identify and quantify different structural phases, determine crystallinity, determine crystalline network parameters, gauge residual mechanical stress, among many other properties of powdered or whole materials, solids or liquids. In the analysis of solid samples in refraction mode, the sample is irradiated by an X-ray beam which is subsequently refracted at certain angles according to the crystalline structure, according to Bragg’s Law of Refraction:

nλ = 2d sinθ

where n is the order of refraction (n = 1, 2, …), λ is the wavelength of the incident beam, d is the spacing between atomic planes in the crystal, and θ is the angle formed between the incident beam and the plane of refraction.

Since each substance has a unique spectrum, the relative number, position and intensity of the peaks in a sample allow the different phases present to be identified and therefore their qualitative composition to be determined. The quantitative composition can be determined using a calibration curve. Alternatively it can be calculated using the RIR (Reference Intensity Ratio) method, where a pre-established proportionality factor is used between the most intense reflections of each phase and a standard substance (Al₂O₃-corundum).

APPLICATION EXAMPLES

Characterization of API

Batch comparison of API

Identification of additives in electrical cable coatings

Quantification of different phases in biomaterials

Phase characterization in ore

Phase characterization in slag

Rheology is the study of the flow and deformation of materials when a force is applied and usually using rheometer. Rheological properties are referred to all fluid materials such as dilute solutions of polymers and surfactants through concentrated protein formulations; semi-solid materials such as pastes and butter, molten materials or solids such as polymers and asphalt.

Many materials and formulations exhibit complex rheological properties, whose viscosity and viscoelasticity differ depending on the external conditions applied, such as stress, pressure, time and temperature. Internal sample differences, such as chemical nature, concentration and stability, and the type of formulation are also key factors for rheological properties.

The type of rheometer required for measuring these properties often depends on the appropriate shear rates and time frames, as well as the sample size and viscosity.

APPLICATION EXAMPLES

Viscosity profiling

Viscoelastic fingerprinting for material classification: solid or liquid behavior

Optimization and evaluation of dispersion stability

Thixotropy determination;

Impact of polymer molecular architecture on viscoelasticity for processing and end-use performance;

Benchmarking food and personal care products for pumpability or spreadability

Complete curing profile for bonding or gelling systems

Pre-formulated screening for therapeutics, particularly biopharmaceuticals

NTA

Liquid Density

Refractive Index

Elemental Analysis (DUMAS and CHNS)

Contact Angle