Superamphiphobic Surfaces with Controllable Adhesion Fabricated by Femtosecond Laser Bessel Beam on PTFE

In this study, a facile method is presented to fabricate superamphiphobic surfaces with controllable adhesion on polytetrafluoroethylene (PTFE), for the first time, using femtosecond laser Bessel beam. Compared to previous structures mostly based on 1D microstructure produced by Gaussian beam, the surfaces are characterized by highly uniform 2D periodic hill-groove structures covered with extensive porous-mesh nanostructures. Most significantly, the 2D hill-groove structures have a very high-aspect-ratio since the energy distribution of the Bessel beam is more uniform over a longer focusing range. Moreover, the profile of the obtained microstructures is a nearly perfect semi-spherical shape. As a result, the processed surfaces become superamphiphobic, exhibiting a contact angle of 166 degrees for water and 160 degrees for oil, respectively. Furthermore, the surface adhesion can be controlled from ultralow to ultrahigh by adjusting the period of the hill-groove 2D-patterned structures. It is demonstrated that the ultralow adhesion surfaces show excellent antifog and anti-icing properties, while the ultrahigh adhesion surfaces can be used for water and oil collection. Both surfaces have a good mechanical stability and are stable over a wide range of temperatures. The superamphiphobic PTFE surfaces with tunable adhesion can be used for self-cleaning, microfluidic systems, and harsh environments.