Mechanically durable superhydrophobic PDMS-candle soot composite coatings with high biocompatibility

To realize practical applications, the development of superhydrophobic coatings with high durability against harsh environmental conditions has been of interest, especially coatings that are susceptible to mechanical damage. Herein, we present mechanically durable superhydrophobic polydimethylsiloxane (PDMS)-candle soot (CS)-based composite coatings through simple and rapid casting and soot processes, which can be fabricated on various substrates, such as glass, woods, stainless steel meshes, and plastics. The reported extremely water-repellent coatings consist of a PDMS basic binding layer, candle soot clusters (CSC), and an outside CS layer, which has exhibited long-lived superwettability and resistance against mechanical damage in multi-cycle abrasion tests and ultrasonication treatments over a long duration. The resulting mechanical durability was mainly a result of three-dimensional topography-protected and carbon nanoparticle-mixed structures, which decreased the contact area and created highly hydrophobic bulk coatings. Moreover, the durable performances of the three types of CS-based superhydrophobic coatings to resist mechanical damage, involving CS, PDMS-CS, and PDMS-CSC-CS coatings, were compared on a glass substrate, and the results indicated higher robustness of the present PDMS-CSC-CS coatings. In addition, it showed higher biocompatibility than a PDMS film surface, and can therefore be employed as a promising material for further modification for applications in prospective multifunctional biomedical devices.