Cross‐flow microfiltration, using a microporous membrane, is a well‐established technique for wine clarification in oenology because of its cost‐effectiveness and high‐throughput. However, membrane fouling remains a significant issue for wine filtration in high‐throughput systems. Herein, an approach for in situ real‐time monitoring of fouling in filtration systems using a conductive filtration membrane and a model fluid for filtration is reported. The membrane is fabricated by embedding poly(3,4‐ethylenedioxythiophene) into an electrospun sulfonated polystyrene‐block‐poly(ethylene‐ran‐butylene)‐block‐polystyrene microporous membrane, producing a conductive microfiltration membrane. Measurement of the resistance of the conductive membrane during filtration with the fouling solutions containing pectin, as one of the major foulants in unfiltered wine and pre‐fermentation grape juice, shows a time‐ and concentration‐dependent response. This work opens a door to new methodology for in situ monitoring of fouling processes in wine and juice filtration systems.

A filtration membrane was modified with a conducting polymer coating for the permeate flux control through an electric input. The filtration membrane was first soaked in ferric chloride to load the oxidants on the membrane surface, followed by vapor-phase polymerization of 3,4-ethylenedioxythiophene (EDOT). Optimizations were carried out to balance the filtration performance and the electrical performance of the conductive membrane. Infrared spectroscopy and X-ray photoelectron spectroscopy confirmed the formation of PEDOT coatings on the membrane surfaces. Spectroelectrochemistry was carried out to confirm the reversible redox reactivity of the PEDOT coating when charged and discharged at +1 and −1 V. The permeate flux of the conductive membrane showed a switchable behavior during the PEDOT charging/discharging cycles. The swelling behavior of PEDOT coatings on the membrane in the charging/discharging cycle was confirmed by electrochemical atomic force microscopy with the ingress/egress of dopant ions being responsible for the membrane's switchable flux properties. The reversible redox switching behavior of the conductive polymer coating on the filtration membrane provides a potential application for permeate flux control through an electric input.

This work addresses the challenge of surface modification of porous, electrospun fiber mats containing an insoluble conducting polymer coating. Herein, a novel methodology of grafting a polymer brush onto conducting polymer fiber mats is developed that employs filtering of the polymerization solution through the fiber mat. An electrospun sulfonated polystyrene‐poly(ethylene‐ran‐butylene)‐polystyrene (sSEBS) fiber mat is first coated with a layer of conducting copolymer bearing an Atom Transfer Radical Polymerization (ATRP) initiating functionality (PEDOT‐Br). The surface‐initiated ATRP from the fibers’ surface is then carried out to graft a hydrophilic polymer brush (poly(ethylene glycol) methyl ether methacrylate) by means of filtering the polymerization solution through the fiber mat. Scanning electron microscopy (SEM) images reveal a progressive change in the morphology of the fiber mat surface with the increasing volume of the filtrated polymerization solution, while energy dispersive X‐ray spectrosdcopy (EDX) spectra show a change in the atomic oxygen to sulfur (O/S) ratio, therefore confirming the successful grafting from the fibers’ surface. The conductive fiber mat grafted with hydrophilic brushes shows a 20% reduction in the non‐specific adsorption of bovine serum albumin (BSA) compared to a pristine fiber mat. This study is a proof‐of‐concept for this novel, filtration‐based, surface‐initiated polymerization methodology.