Self-assembled block polymers are an excellent platform for producing the next generation of mesoporous membranes. Large areas (>500 cm2) of membrane that contain a high density of singly-sized pores can be produced readily from these novel macromolecules using the self-assembly and non-solvent induced phase separation (SNIPS) technique. However, the block polymer membranes produced thus far contain pore walls that are lined by a limited number of chemical functionalities, whereas tailored pore chemistries are preferred. In this work, we address this shortcoming by producing triblock-polymer-derived membranes that can be chemically tailored, in a facile and scalable manner, to the specific needs of a multitude of applications.This talk will discuss efforts to fabricate membranes from triblock polymers for the removal of dilute contaminants from aqueous solutions. Specifically, the SNIPS process is used to fabricate membranes from a poly(isoprene-b-styrene-b-N,N-dimethylacrylamide) (PI-PS-PDMA) triblock polymer. Using a simple process after membrane fabrication, the PDMA groups that line the pore walls are converted to polyacrylic acid (PAA), which can be reacted further to functionalize the membrane pores. Advanced microscopy characterization techniques (TEM, SEM, AFM) are used to systematically explore the nanostructure of the block polymer membrane at each step of the process (i.e., during the fabrication of the parent membrane, the conversion step, and the subsequent pore wall functionalization). These characterization techniques show that the SNIPS process produces an asymmetric membrane with a thin active layer, which contains 1013 self-assembled pores per m2 of membrane with diameters that can range from 2-20 nm, depending upon the molecular weight of the PI-PS-PDMA template. These membranes maintain their mesoporous structure following the conversion and functionalization steps. Additionally, transport tests are conducted at each stage to quantify the hydraulic permeability and solute rejection capabilities of the membrane. This combination of materials characterization and transport testing lays the groundwork for the development of structure-property-performance relationships that can guide the use of this versatile membrane platform in water purification applications.

Functional filtration membranes with chemically-tailored pore walls from triblock polymer templates

248th National Meeting (2014)

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