When does electrostatic adhesion occur?

Electrostatic adhesion occurs when conducting materials transfer electrons, leading to the development of static electrical charges on the surfaces of the materials. When two objects come into contact, electrons can move from one surface to another, resulting in one material becoming negatively charged and the other positively charged. This difference in charge creates an attractive force between the two surfaces, which is what is referred to as electrostatic adhesion.

This phenomenon is commonly observed in various contexts, such as in the interaction between balloons and hair, or when certain materials stick to surfaces after being rubbed together. The transfer of electrons is crucial to this process as it is the charge imbalance that facilitates the attraction between the objects once they are separated.

The other options do not accurately describe the conditions necessary for electrostatic adhesion. Heating or cooling materials, for instance, does not inherently result in the transfer of electrons leading to charge separation but affects molecular dynamics or physical properties instead. Pressing materials together tightly may enhance physical adhesion or mechanical locking but does not primarily rely on electrostatic forces.