The interfaces laboratory is equipped to perform measurements of properties of the interface between fluids and to characterize properties associated with suspensions and emulsions, such as droplets and particle size distribution.

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Main available equipment:

• Polarized optical microscope with shear module

Our laboratory has a Nikon Eclipse LV100 optical microscope equipped with five magnification objectives ranging from 5x to 100x. In addition, this equipment has a polarized light system that allows the observation of birefringent materials. Applications include visualizing the microstructures of emulsions and paraffinic oils. We can determine the droplet size distribution of an emulsion or observe the formation of crystals using the information received from the microscope.

Linkam’s Cryo-CSS450 accessory is a device that allows you to visualize the sample being sheared. It features sample cooling and heating in the range of -50°C to 450°C.

• Tensiometer

The Kruss GMBH K100C and Lauda TE 1C tensiometers measure surface properties such as surface/interfacial tension, contact angle and critical micellar concentration (CMC). It can be used in several systems with fluid interfaces, being a crucial tool to evaluate the physicochemical properties of surfactants relevant to the study of complex interfaces.

• Langmuir Trough

The Langmuir Trough is formed by two movable barriers and two main compartments for the fluid phases with the aid of a Wilhelmy plate, gently located at the air-water interface. It is a highly effective tool for studying thin layer coatings and surfactant adsorption.

We have the Langmuir-Blodgett cell model KSV NIMA KN 1004 from Biolin Scientific. This is used to investigate the swelling/compression properties of interfacial films. Through it, it is possible to obtain interface pressure isotherms by compression area or molecular area. The vessel can be coupled to shear rheometers and microscopes to better assess the morphology and mechanical properties of the films formed at fluid-fluid interfaces.

• Accessories for interfacial rheology measurements:

The DHR-3, ARES-G2 and MCRs rheometers are equipped with accessories specialized in obtaining interfacial measurements. The options are the Double Wall Ring (DWR), Du Nouy Ring and bicone interfacial system for measuring viscous and viscoelastic properties through contact with the fluid-fluid interface. In addition, the Langmuir Trough that can be associated with such rheometers to investigate the effect of surface pressure on interfacial rheological properties.

• Turbiscan

The Turbiscan LAB is an equipment used to evaluate the stability of emulsions and concentrated foams. Data acquisition is carried out along the object of analysis according to the scan frequency programmed by the user to obtain the curve of transmission versus backscattering, which determines whether the suspension/emulsion is stable or unstable. This equipment offers immediate quality control, without changing the formulation and without the need for dilution.