Development of diamond-like-carbon coated abaca-reinforced polyester composites for hydrophobic and outdoor structural applications

This study presents the development of abaca fabric-reinforced polyester composites for outdoor applications having hydrophobic surface quality and enhanced mechanical properties. Diamond-like carbon (DLC) coatings of 20–135 nm was deposited without interlayer, directly on 2.5-mm thick abaca/polyester composites using filtered cathode vacuum arc system. Before film deposition, the substrate plasma etching was performed for better film adhesion. Microstructural studies include Raman Spectroscopy that confirms the formation of DLC structure with higher graphitic contents; Scanning Electron Microscopy and Atomic Force Microscopy for observation of coating coverage, surface roughness, and topography, respectively. Contact angle measurement was conducted to investigate surface wettability. After achieving hydrophobic surface quality from 76° to 98°, the research was extended to get better structural properties. The nanohardness of uncoated polymers was enhanced from 536 to 2513 MPa by introducing 150-nm Ti interlayer while keeping the same hydrophobic properties. Detailed tribological studies were carried out to understand wear behavior of uncoated and DLC-coated polymer composites with and without interlayer effects.