Designing Non-Charging Surfaces from Non-Conductive Materials

Static charge generated from contact of solid surfaces is ubiquitous, and can give rise to a wide variety of undesirable consequences. These effects may cause little annoyances in daily lives (e.g., an electric shock when one touches a door knob), a reduction in efficiency in many industrial processes (e.g., charged particles that adhere to surfaces of vessels can hinder heat transfer), damage to equipment (e.g., electronics), and potentially hazardous situations (e.g., explosions). For many decades, the general strategy to address problems arising from contact electrification is to make surfaces conductive (e.g., by adding antistatic agents) in order to dissipate charge. However, this method may not be effective when the contacting material is insulating; in addition, modification of the materials to make them conductive may change the properties of the materials in undesirable ways. Here, we introduce a general strategy of fabricating non-charging surfaces – by copolymerizing a molecule that has the tendency to charge positively with another molecule that has the tendency to charge negatively. At an appropriate proportion of the two molecules, the copolymer can be fabricated to resist charging against a reference material. Importantly, this polymer naturally resists charging against the reference material and is insulating; that is, this strategy does not require the material to be conductive. We showed that the copolymer can prevent the adhesion of micron-sized particles due to attractive electrostatic force. In addition, the strategy is general: different copolymers can be fabricated to resist charging against many different contacting materials. Thus, it is possible to fabricate a class of non-charging materials with properties that are compatible to different applications.