Bilayer Compounded Polytetrafluoroethylene Membrane for Enhanced Oil-Water Emulsion Separation

In order to achieve efficient and durable oil-water emulsion separation,the membranes possessing high separation efficiency and mechanical strength attract extensive attention and are in great demand.In present study,a kind of polytetrafluoroethylene(PTFE)-based bilayer membrane was fabricated by electrospinning fibrous PTFE(fPTFE)on an expanded PTFE(ePTFE)substrate.The morphological observation revealed that the fibrous structure of the fPTFE layer could be tailored by controlling the formulation of spinning solution.The addition of appropriate polyoxyethylene(PEO)would make the fibers in the fPTFE layer finer and more uniform.As a result,the compounded membrane exhibited a small pore size of approximately 1.25µm and a substantial porosity nearing 80%.This led to super-hydrophobicity,characterized by a high water contact angle(WCA)of 149.8°,and facilitated rapid oil permeation.The water-in-oil emulsion separation experiment further confirmed that the compounded membrane not only had a high separation efficiency closing 100%,but such an outstanding separation capacity could be largely retained,either through multiple cycles of use or through strong acid(pH=1),strong alkali(pH=12),or high-temperature(100°C)treatment.Additionally,the mechanical behavior of the bilayer membrane was basically contributed by that of each layer in terms of their volume ratio.More significantly,the poor creep resistance of fPTFE layer was suppressed by compounding with ePTFE substrate.Hence,this study has laid the groundwork for a novel approach to create PTFE-based compounded membranes with exceptional overall characteristics,showing promise for applications in the realm of emulsion separation.

C60(OH)n-loaded nanofibrous membranes protect HaCaT cells from ROS-associated damage

Environmental stress factors could lead to the excess generation of reactive oxygen species（ROS） that induces various forms of skin damage related to oxidative stress. Polyhydroxylated fullerene derivative C（60）（OH）n, acting as an effective agent for prevention of skin aging, is widely used in the lotion and sunscreens in the field of cosmetics, but rarely used in the masks. In this study, we prepared C（60）（OH）n loaded nanofibrous membranes to protect human keratinocyte cells from ROS-associated damage and suppress the elevation of intracellular ROS and Ca（2＋） along with the apoptotic cell death. Two FDAapproved biodegradable polymers, PLGA and PCL, have been used for making the electrospun nanofibers,with C（60）（OH）n added to the polymers as an antioxidant. The nanofibrous membranes with good biocompatibility might be potentially applied in clinical practice to reduce skin aging.