Colloidal Analysis Techniques

Course goals

After completion of the course, students should

- have basic knowledge of several characteristic physical properties of colloidal dispersions (viscosity, static and dynamic light scattering, aggregation, surface charge, electrophoresis, conductivity, sedimentation rate, osmotic pressure, …),
- understand the general principles of the discussed experimental methods used to characterize colloidal dispersions and other soft matter,
- understand which information is obtained via the discussed techniques and be aware of assumptions made in the interpretation of the measurements,
- be able to perform simple numerical calculations to deduce quantitative colloidal properties from typical measurement data, and
- be able to read and comprehend scientific publications that present results obtained using the discussed analytical techniques.
 

Content

This course examines the physical properties of colloidal dispersions and other soft matter from an experimental perspective. Several characterization techniques used in research laboratories (at UU and elsewhere) are presented, and examples are given of how they can be applied on, for instance, foods, paints, biological fluids, and inorganic particles prepared via wet chemical methods for heterogeneous catalysis or research on quantum dots. For each technique, the physical principles are examined, as well as the interpretation of typical measurement data. The main topics are:

- Rheometry (viscosity, shear stress, shear rate, yield stress, components G’ and G” of the complex shear elastic modulus)
- Static and dynamic light scattering (SLS—particle sizing from the angle dependence of scattered light intensity—and DLS—particle sizing from the time dependent scattering of particles that exhibit Brownian motion)
- Osmometry (various technical approaches including membrane osmometers, vapor pressure osmometers, and freezing point osmometers)
- Laser-Doppler electrophoresis (determination of electrophoretic mobility and interpretation in terms of the surface charge and zeta potential of the colloidal particles)
- Conductometry of electrolyte solutions (dependence on the types of ions, temperature, and concentration)
- The combination pH electrode and other examples with liquid junction potentials (diffusion potentials and ionic transport numbers)
- Analytical centrifugation (sedimentation velocity and sedimentation equilibrium)
- Magnetomery (types of magnetic materials and the corresponding dependences of their magnetization as a function of the applied external magnetic field)

This 3.75 EC course and the Colloidal Dispersions course (SK-MCODI, 3.75 EC) are recommended for students who want to do research on colloids or other soft matter in the Physical and Colloid Chemistry group or the Soft Condensed Matter group.