Effects of Charge

Forces Acting on Particle

For a single, dielectric, spherical particle with a uniform charge distribution

F_Im = 12 nN

Van der Waals attraction:

F_VW = 625 nN

Define R_crit by F_VW = F_Im

If:A = 10^-19 Jz₀ = 4 Å

Þ R_crit = 0.5 mm

For R < R_crit:van der Waals dominated

For R > R_crit:electrostatic dominated

However:Both forces contribute to adhesion.