water such as proteins, oils, and microorganisms is one of the major drawbacks in the membrane fi ltration because it can decrease the water permeation fl ux causing a subsequent increase in energy consumption for the fi ltration process. [ 2,3 ] Biofouling layer formed by the microorganisms on the membrane surfaces can clog and/or contaminate the membrane surfaces, thus preventing effective water purifi cation. [ 3h , 4 ] Rejection of heavy metal ions in waste water is another major concern in the membrane fi ltration process.Since membrane surface properties are key factors to the understanding and control of physico-chemical phenomena in the membrane fi ltration process, membrane surface modifi cations using blending, surface coating, and surface grafting methods have been applied to overcome the disadvantages of the process. [ 3a,d , 5 ] For example, a polymer with an ionic/ligand moiety was coated on a membrane surface to impart heavy metal ion removal properties, [ 5b ] and poly(ethylene oxide) (PEO) was incorporated into poly(acrylonitrile) (PAN) membrane by blending to enhance antifouling property against proteins. [ 3e ] Most of the membrane surface modifi cation strategies have focused on resolving one of the deleterious properties of each particular application. However, to our knowledge, any membrane surface modifi cation method to impart all the advantageous properties including the antifouling, antimicrobial, and heavy metal ion removal properties has not yet been reported.Plant-derived polyphenols have attracted signifi cant interests due to their broad chemical versatility, radical scavenging ability, metal ion complex formation, and antimicrobial properties. [ 6 ] They are easily obtained from general plants such as green tea, fruits, and fl owers, and also commercially available with low cost. [ 6a , 7 ] Polyphenol derivatives can be broadly used for surface coating applications because their catechol (1,2-dihydroxyphenyl) and/or gallol (1,2,3-trihydroxyphenyl) groups can easily adhere to the surfaces of substrates, forming covalent and/or noncovalent bonding structures. [ 5a,d , 6d , 8 ] For example, dopamine, a polyphenol derivative having the catechol moiety, has been applied as an antifouling coating material for fi ltration The membrane fi ltration process has received much attention as one of the most promising water purifi cation techniques. However, it still has several disadvantages, such as organic-, oil-, and biofouling, membrane contamination by microorganisms, and the diffi culty in rejecting heavy metal ions, which are closely related to the membrane surface properties. Various approaches have been used to prepare membranes with antifouling, antimicrobial, or heavy metal ion removal properties on their surfaces. However, membranes with all these properties have not yet been reported. It might be possible to prepare membranes with such multifunctional properties by modifying the membrane surfaces with various organic and/or inorganic functional materials using multiple chem...