In this study, superhydrophobic dual layer membranes with highly porous structure were fabricated using electrospinning and electrospraying techniques. Electrospinning method was used to produce the support nanofibrous layer using polyvinylidene fluoride-co-hexafluoropropylene (PH) as the polymer and a mixed solvent system of N,N-Dimetylformamide (DMF) and acetone. Afterwards, hydrophobic, functionalized TiO₂ nanoparticles were deposited on the surface of the support layer using the electrospraying technique. TiO₂ chemical functionalization and their deposition on the support layer were investigated by Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy. The effects of different concentrations of TiO₂ nanoparticles (100 and 200wt%) and PH (7–9wt%) in the electrospraying solution on the dual layer membrane characteristics, such as surface morphology, pore size, porosity, water contact and sliding angle, mechanical properties, and liquid entry pressure (LEP) were thoroughly examined. The results show that porous superhydrophobic nanofibrous membranes with water contact angles higher than 150 ° , sliding angles lower than 10 ° , and low contact angle hysteresis were successfully fabricated. Consequently, the prepared membranes showed comparable LEP with the commercial polyvinylidene fluoride (PVDF) membrane, but at much higher porosity (>85%) and mean pore size (>0.70 μ m). Performance of the dual layer membranes, along with the single layer PH and commercial PVDF membranes, were carried out in a direct contact membrane distillation setup. The superhydrophobic nanofibrous membrane showed noticeably more stable operation compared with the neat PH membrane and consistently higher flux (38.71∓1.105Lm⁻² h⁻¹) than the commercial PVDF membrane (26.64∓0.97Lm⁻² h⁻¹) during 24h of operation.

中文翻译：

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用于高通量膜蒸馏的超疏水双层功能化二氧化钛/聚偏二氟乙烯-六氟丙烯共聚物（TiO2 / PH）纳米纤维膜

在这项研究中，使用静电纺丝和电喷雾技术制造了具有高度多孔结构的超疏水双层膜。使用静电纺丝法，以聚偏二氟乙烯-六氟丙烯共聚物（PH）为聚合物，以及N，N-二甲基甲酰胺（DMF）和丙酮的混合溶剂体系生产载体纳米纤维层。然后，使用电喷雾技术将疏水的，官能化的TiO ₂纳米颗粒沉积在支撑层的表面上。通过傅立叶变换红外光谱（FTIR）和扫描电子显微镜研究了TiO _2的化学功能化及其在支撑层上的沉积。不同浓度的TiO _2的影响电喷雾溶液中的纳米颗粒（100和200wt％）和PH（7–9wt％）对双层膜的特性，例如表面形态，孔径，孔隙率，水接触和滑动角，机械性能和液体进入压力（ LEP）进行了彻底检查。结果表明，成功制备了水接触角大于150°，滑动角小于10°，低接触角滞后的多孔超疏水纳米纤维膜。因此，制备的膜显示出与市售的聚偏二氟乙烯（PVDF）膜相当的LEP，但是具有高得多的孔隙率（＞ 85％）和平均孔径（＞0.70μm）。双层膜以及单层PH和商用PVDF膜的性能，在直接接触膜蒸馏装置中进行。与纯净PH膜相比，超疏水纳米纤维膜表现出明显更稳定的操作，并且通量始终较高（38.71∓1.105Lm^-2 ħ ^-1）比商业PVDF膜（26.64∓0.97Lm ^-2 ħ ^-1操作的24小时期间）。