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Methods:

Experimental methods available in the Department of Chemical Engineering:

 

A: Size and mass distributions, diffusion and virial coefficients, and zeta-potential of colloid particles and macromolecules:

  • Static light scattering (SLS) and dynamic light scattering (DLS) for size distribution, molecular weight distribution, and virial coefficients.

  • Zeta-potential of solid particles and emulsion droplets by electrophoretic light scattering.

  • NMR for molecular diffusion coefficient and drop size determination.

  • Gel electrophoresis.

  • Thin layer chromatography.

 

B: Interfacial Tension and Adsorption:

  • Wilhelmy plate method.

  • De Nouy ring method.

  • Maximum bubble pressure method (MBPM).

  • Drop shape analysis (DSA) of pendant and sessile drops.

  • Stopped jet method for fast adsorption kinetics (from 0.05 s up to 5 minutes).

  • Capillary pressure tensiometry (CPT) for equal density liquids.

  • Langmuir trough.

  • Ellipsometry for adsorption and adsorption kinetics on fluid and solid surfaces.

  • ΔV potential and Brewster angle microscopy (BAM).

  • Spinning drop method for ultra-low interfacial tensions.

 

C: Interfacial rheology and Bulk rheology:

  • Oscillating drop method (ODM) by drop-shape analysis (DSA) and by capillary pressure tensiometry (CPT).

  • Expanding drop method (EDM).

  • Langmuir trough with oscillating barriers.

  • Sliding solid particle method.

  • Rheometer for surface shear rheology.

  • Rotational rheometer for bulk rheology of liquids, foams, emulsions, dispersions.

  • Squeeze-flow rheometry.

 

D: Thin Liquid Films (TLF):

  • Foam and emulsion films in a horizontal capillary cell.

  • Foam and emulsion films in a porous plate cell.

  • Foam Films with exchange of the film-forming liquid.

  • Vertical foam films on different frames (rectangular, circular, 3- and 4- legs, etc.).

  • Film trapping technique (type of surface force apparatus) for measuring the interaction of micron sized drops.

 

E: Contact Angle Measurement and Surface Energy Determination:

  • Interferometric methods for contact angles of thin films.

  • Shape of single interfaces and thin films by differential interferometry.

  • Contact angles of micron size particles by interferometric method and film trapping technique.

  • Goniometric method for contact angles of fluid particles on solid surfaces or solid particles attached to fluid interfaces.

 

F: Foams and Emulsions:

  • Growth and stability of foams by Ross-Miles test.

  • Growth and stability of foams by gas barbotage (Bickerman’s method).

  • Growth and stability of foams by Bartsch method (manual and automated).

  • Antifoam effect in Automated shake test.

  • Membrane emulsification.

  • Emulsification in a narrow gap homogenizer.

  • Formation of fine emulsion and suspensions with a laboratory rotor-stator homogenizer Ultra Turrax.

  • Emulsion stability by centrifugation.

  • Drop and bubble size distributions by video-microscopy.

 

G: Model Studies of Dispersions:

  • Kinetics of solubilization by optical observations of diminishing drops.

  • Drop removal in axisymmetric flow field.

  • Drop and particle deposition on solid surfaces.

  • Lifetime of rising bubbles and drops.

  • Lifetime of colliding drops and bubbles.

 

H: Spectral and Optical Characterization of solutions and thin layers:

  • Refractometry of high accuracy (5 significant digits) for measuring refractive indices of liquids, solutions, and suspensions.

  • UV-VIS spectrophotometer for measuring low surfactant/protein concentrations.

  • Method for measuring the transmittance, the reflectivity and the scattering of light by the particulate layers - by research photometer or photomultiplier.