Surfaces modification of HDPE specimens using waxes for thick fluid “Roll‐off”

Abstract In this research work, two natural and one synthetic wax were used for the inner surface coating of a high‐density polyethylene (HDPE) specimen to make it self‐lubricating and reduce wettability. This includes solvent etching by chromic acid and further impregnating the substrate with waxes. The chromic acid etching of the HDPE specimen results in changing the surface properties, leading to essential surface roughness. These surfaces are further functionalized with a natural wax‐like, carnauba wax, candelilla wax and synthetic wax‐like, erucamide wax that produces a durable, repellant, and fluid roll‐off surface. For impregnation, a coating on the substrate waxes used was a non‐toxic, self‐lubricating coating material and exhibited reduced wear and friction. Surface properties of HDPE surfaces, like contact angle measurement, spreading coefficient, wetting energy, and work of adhesion checked with the help of a contact angle analyzer. Surface morphology was investigated by scanning electron microscopy. Amongst these three waxes, synthetic wax (erucamide) exhibits a higher contact angle and increases hydrophobicity. Material flow test carried out with a thick fluid like ketchup. This test also suggests that erucamide wax gives better fluid repellant properties and a maximum amount of thick fluid roll‐off.