Electrostatics is everywhere

The term “electrostatics” is ubiquitous. We are confronted with electrostatics in nature and nearly all people have had experience with it. Static electricity was already discovered in amber by Thales of Miletus in approximately 550BC.

Electrostatics
What is electrostatics?

In order to understand electrostatics better, one needs to look closer at the microscopic composition of objects and materials. Every object, body, liquid and gas contains positive and negative electrical charges that are normally balanced. This means, that the material is electrically neutral. Intensive contact between any materials, and subsequently their separation or friction, causes negative charges to be pulled out of the one material and taken up by the other. This creates an imbalance of the charge carriers in the materials. They are now electrically charged.

One material becomes positively charged, while the other becomes negatively charged. The rule states that materials which have a high permittivity (e.g. PA, wool, cellulose, glass) mainly become positively charged, while a low permittivity (e.g. PE, PTFE, PS, PVC) leads to a negative charge. Smooth surfaces, high speeds and higher contact pressures create a stronger charge. Even temperature and humidity (e.g. in the summer and winter) impact the strength of the resulting charge.

Example: thunderstorms – electrostatics in nature

Thunderstorms demonstrate the most impressive effects of electric charge through friction. As thunderclouds grow, the water particles inside separate their charges through friction and atomization. The electrical field grows until the voltage equals several hundred million volts. Eventually, the field strength exceeds a critical threshold. This creates a gigantic short-circuit, the lightning bolt. Although the results of electrostatic charge can be beautiful during a storm, they can cause disruptions in industrial environments. In most of these cases, it is definitely not wanted.

Production optimization through electrostatics

In production, unwanted electrostatic charges can interfere with various processes. The following problems often occur:​

 

  • Products stick together
  • Materials repel each other
  • Dust is attracted
  • Sparking occurs

These problems arise because one material becomes positively charged and another negatively charged. The rule is that materials with high permittivity (e.g., PA, wool, cellulose, glass) mainly become positively charged, while lower permittivity (e.g., PE, PTFE, PS, PVC) leads to a negative charge. Smooth surfaces, higher speeds, and higher contact pressures in production contribute to greater charging. Temperature and humidity (e.g., summer and winter) are also important factors in the amount of charging that occurs.