Powders
Suspension
Click to enlarge images. Suspending the particles in a liquid and pipetting them onto a substrate is another way to disperse a single layer of particles on a substrate. The choice of liquid is important. Some liquids, like water, have a high surface tension that forces particles to the outer edge of the droplet, leading to unwanted aggregation. This problem can often be solved by suspending the particles in an organic solvent with a low vapor pressure, such as acetone or alcohol. The solvent has lower surface tension and dries before the aggregation can take place. Be aware, however, that an organic solvent may dissolve or etch certain types of particles, such as polymers. |
