Graphene/polymer nano-composites for antibacterial surfaces

Graphene is a material with extraordinary properties: it is 200 times stronger and 100 times more resistant than steel, it is a semiconductor with a zero band gap, it has the highest conductivity of electricity and heat, it is characterized by flexibility, transparency, stability, and high idrophobicity, and it has the highest melting point of any material in vacuum. Therefore, it is not surprising that graphene is increasingly finding wide application in many field. Unfortunately, such outstanding properties are exhibited only by high-quality single-layer graphene, that can be produced only by using sophisticated methods as Chemical Vapour Deposition. To this respect, it is worth to note that several polymer composites containing graphene were developed because the insertion of graphene can change dramatically their properties. In this framework, we studied the properties of polymer/graphene coatings, developed at DICMA Sapienza, with high graphene content to realise antibacterial surfaces. Antibacterial surfaces can act on the adhesion phases as a non-stick agent against bacteria. Once the bacteria adhere, the surfaces can act on the bacterial inhibition and on the destruction of the membrane, showing a bactericidal behavior. By increasing the concentration of GNP, surface scanning Raman spectroscopy showed that more ordered flakes with gradually larger crystals are inserted in the polymer matrix, while confocal optical microscopy shows an increase in surface roughness. The bacterial cells could be affected by these graphene-based nanocomposite since the surface roughness peaks corresponding to graphene flakes may directly affect bacterial viability by increasing the surface contact area and, consequently, the piercing action of exposed graphene flakes.