A.T. Abdulhussein, G.K. Kannarpady, A.S. Biris
University of Arkansas at Little Rock,
Keywords: PVDF membrane, PTFE target, self-cleaning, superhydrophobic
Summary:Due to their outstanding corrosion resistance, wear resistance, thermal stability, and chemical stability, polyvinylidene fluoride (PVDF) membranes are extensively used for membrane distillation, membrane contactor, oil/water separation, and wastewater treatment. Modifying a PVDF membrane with a superhydrophobic nano-coating of polytetrafluoroethylene (PTFE) has been shown to enhance the membrane’s self-cleaning ability, making it even more appealing for these applications. In this work, we used pulsed laser deposition (PLD) to coat PVDF substrates with PTFE thin films at room temperature. To study the effect of the thickness and morphology of the PTFE films on PVDF, the PTFE was deposited at different deposition times (15, 30, 45, 60, and 90 min). SEM analysis showed that PTFE particulates grew uniformly on the PVDF membrane surface, forming a rough and uniform film. Surface roughness was analyzed by atomic force microscopy, which revealed that roughness increased as deposition time increased up to 45 minutes. The highest water contact angle, 155˚ with negligible contact angle hysteresis, was observed for the sample with 45-minute deposition time. The elemental and chemical analysis, performed using x-ray photoelectron spectroscopy, showed the peak intensity of the coated samples’ C-C bond to be stronger than that of the uncoated PTFE target samples. In summary, this study produced a superhydrophobic PVDF membrane with outstanding self-cleaning properties using a convenient one-step technique without a wetting process.