Banca de DEFESA: LUIZ HENRIQUE PINHEIRO DE LIMA

Study of plasma modification of silicone surfaces in drag reduction

superhidrophobic surface, drag reduction, PDMS, plasma, Chemical Vapour deposition.

In this work it was proposed to produce plasma surface treated silicone surfaces that can promote the reduction of drag and improve the wear reduction of customized silicone devices that need drag reduction, in addition to analyzing the mechanical properties of the surfaces produced. Superhydrophobic surfaces (SSH) have high water repellency and have been studied as an alternative mechanism to reduce drag. The alterations promoted on the surface of Sylgard® due to the deposition of substances such as: acetylene, argon and oxygen, through the plasma treatment has presented the phenomenon of drag reduction on cylindrical surfaces proposed in predefined diameters and lengths. The drag reduction (RA) for the flexible tubes was evaluated on a rheometer bench, in the rotations per minute variations of 50 rpm, 100 rpm, 250 rpm before and after plasma deposition. The surface, morphological and chemical changes were confirmed by Scanning Electron Microscopy (SEM), Fourrier Transform Infrared (AFTIR), Atomic Force Microscopy (MFA) analyzes on flat plates, waiting for the impression of a rough structure at the nanometer scale with deposition of chemical elements from the polymerizing solution through the plasma. The treated samples showed less resistance to water flow, tested through the imposition of torque on the tubes. The argon samples showed the best drag reductions even under laminar flow.