{"id":8045,"date":"2018-04-13T08:00:08","date_gmt":"2018-04-13T14:00:08","guid":{"rendered":"https:\/\/www.ulprospector.com\/knowledge\/?p=8045"},"modified":"2018-04-20T09:33:15","modified_gmt":"2018-04-20T15:33:15","slug":"pe-electrically-conductive-coatings-nanomaterials","status":"publish","type":"post","link":"https:\/\/ulprospector.ul.com\/8045\/pe-electrically-conductive-coatings-nanomaterials\/","title":{"rendered":"Put a Shock in your Paint: Electrically-Conductive Coatings and Miracle Materials"},"content":{"rendered":"

Electrically-conductive particles<\/strong><\/em> for use in coatings have taken a quantum leap forward in recent years. Revolutionary materials like carbon nanotubes<\/em><\/strong> (CNTs) and graphene<\/em><\/strong> possess 200 times greater strength than steel, with conductivity better than copper. This unique combination of strength, conductivity and high temperature resistance have the promise to impart exceptional properties in coatings that challenge the imagination. This article will discuss and contrast conductive materials with an emphasis on conductive nanomaterials and their potential advantage in coatings applications.<\/p>\n

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More than 200 conductive materials<\/h3>\n

That’s what you’ll find in Prospector\u00ae. Conductive additives, resins, pigments…Find materials faster with Prospector.<\/p>\n

Click here to search for conductive coatings materials now<\/a><\/h3>\n
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Other more commonly used electrically-conductive particles include conductive carbon black, graphite, quaternary ammonium salts, copper, aluminum, silver and combinations thereof. In addition to conductive particles, there are a number of conductive polymers that can provide conductive coatings that may be discussed in a future article. Surface resistivity of coatings is nearly independent of relative humidity. Figure 1 illustrates the structure of graphene, graphene is a two-dimensional structure and can be thought of as a single walled carbon nanotube in sheet form.<\/p>\n

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Figure 1 – Scanning probe image of Graphene showing hexagonal two\u2013dimensional arrangements of carbon atoms<\/figcaption><\/figure>\n\n\n\n\n\n\n
Conductivity = S\/cm or S\/m<\/p>\n

Surface resistivity = \u03a9\/\u25fb (ohms per square)<\/p>\n

Surface resistance = \u03a9<\/p>\n

Volume resistivity = \u03a9 x cm<\/p>\n

Volume (bulk) resistivity = (Resistivity x length x width) \/ height<\/td>\n<\/tr>\n

Volume resistivity<\/u> is a measure of sheet resistivity across defined thickness<\/td>\n<\/tr>\n
Surface resistivity<\/u> is the most common means used to characterize conductive coatings. ASTM D257 is the most widely-used standard for measuring surface resistivity.<\/td>\n<\/tr>\n
Percolation theory:<\/u> As concentration of a conductive material in a coating increases, the conductivity will reach a point where the conductivity will abruptly increase once a critical concentration is reached.<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

Table 1 – Common Terminology of Conductive Materials<\/em><\/p>\n

For electric current flow across a surface, surface resistivity<\/em><\/strong> (ohms\/square) can be defined as the ratio of voltage drop per unit length, to the surface current per unit width.<\/p>\n

Antistatic<\/em><\/strong> refers to the property of a material that inhibits triboelectric charging. Antistatic coatings have a surface resistivity of at least 1 X 109<\/sup>, but less than 1 X 1012<\/sup>.<\/p>\n

Static dissipative<\/em><\/strong> coatings have:<\/p>\n