Effects of Charge

Methods of Measuring Particle Adhesion

1. Centrifugation.
   1. Better on large (R>20 mm)
   2. Slow
   3. Well established technique
   4. Minimal interactions
   5. Good statistics
2. Electrostatic Detachment
   1. Medium to large particles (R>5 mm)
   2. Interaction with electric field
   3. Good statistics
3. Hydrodynamic detachment
   1. Small particles (R<0.5 mm)
   2. Good statistics
   3. Introduces a fluid
4. Atomic force techniques
   1. Measures attractive as well as removal force
   2. Can exert precise loads on particles
   3. Short and variable time scales
   4. Can distinguish force mechanisms
   5. Poor statistics
5. Contact area technique
   1. Good statistics
   2. Forces not directly measured.
   3. Equilibrium measurement
   4. Need spherical particles
   5. Wide range of particle sizes
6. Nanoindentor
   1. Easy to interpret measurements
   2. Readily repeatable
   3. Simulation of particle adhesion rather than actual measurement.
7. Israelachvili Surface Force Apparatus
   1. Uses crossed cylinders rather than particles
   2. Cylinders can be coated with materials of interest
   3. Simulation of particle adhesion