Ultralow hysteresis superhydrophobic surfaces by excimer laser modification of SU-8

We present a new and simple method to produce superhydrophobic surfaces with ultralow hysteresis. The method involves surface modification of SU-8 using an excimer laser treatment. The modified surface is coated with a hydrophobic plasma-polymerized hexafluoropropene layer. The advancing and receding water contact angles were measured to be approximately 165°. The achieved water contact angle hysteresis was below the measurement limit. This low hysteresis can be ascribed to nanoscale debris generated during the excimer laser process

Damping of a vibrating beam

This study examines the vibration in a beam with one fixed end. The set-up consisted of a beam with one end clamped and a rigid plate having the same thickness of the beam, located adjacent to the unfixed end of the beam. The gap between the beam and the plate varied from 4 to 128 μm depending on the length of the beam. From the system behaviour in the small signal regime it was concluded that the frequency ratio of the second and first allowed transverse vibrations is solely a function of the gap size. In the large signal regime energy flow to other vibration modes takes place due to nonlinear effects. These two effects together with the squeeze film damping in the studied structure could be applied in constructing a mechanically isolated and damped substrate plate for a micromechanical sensor, aimed to consumer applications