Atmospheric plasma treatment to improve the surface properties of P3HB coating. A study of the influence of substrate roughness

Polyhydroxybutyrate (P3HB) is a biocompatible polymer. However, its hydrophobic surface can disrupt cell adhesion, which is essential in implanted biomaterials. Atmospheric plasma treatment is an environmentally friendly method that improves surface properties. This study analyzed P3HB coatings obtained on stainless steel by various mechanical interlocking and their plasma process. The surface free energy and the degree of crystallinity of coatings increased with the plasma treatment. Atomic force microscopy analysis showed that roughness improved, and adhesion energy increased by a factor of three after plasma treatment by inserting polar groups analyzed with Raman spectroscopy. Based on this, a mechanism of chemical functionalization by plasma on the surface is proposed. The results depend on the initial properties given by the mechanical interlocking at the metal-polymer interface.