Membranes are an advantageous technology for water separations due to their selectivity and tunability, as well as their lower energy requirements and manufacturing costs. However, membranes are often produced using solvents that pose a great risk to human health and the environment and are consequently heavily (Dong et al., 2021); hence, membranes fabricated using “green” solvents, which are biodegradable and non-toxic, are the focus of much research as possible alternatives. Previously, poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) (Russo et al., 2021) and polysulfone (Lu et al., 2024) membranes have been fabricated using PolarClean® (PC) and gamma-valerolactone (GVL) with acceptable levels of rejection of solutes present in the feed . These membranes have been cast as individual polymers in solvents, or single-layer membranes for specific rejections. Single-layer membranes fabricated using green solvents often suffer from decreased mechanical strength. Therefore, this project aimed to create membranes with two layers of PVDF-HFP and polysulfone polymers in order to maximize rejection. Furthermore, a nonwoven polyester support was used during membrane casting for added mechanical strength. Membranes were also fabricated at 2 polymer concentrations to observe differences in membrane characteristics. Characterization of PC/GVL membranes was conducted through electron microscopy (SEM) imaging, cangle, and tensile testing. SEM imaging allowed a better understanding of membrane morphology by helping us understand surface pore size and shape Contact angle studies revealed 17% PVDF-HFP membranes had greatest hydrophobicity (97.05 ± 10.70º) than 22% bilayer membranes (85.25 ± 9.94º), but differences were not statistically significant. Tensile testing yielded Young’s Moduli for 17% PVDF-HFP, polysulfone, and bilayer supported membranes of 189.14 ± 20.44 MPa, 196.64 ± 3.93 MPa, and .33 ± 11.53 MPa, respectively.
