(822b) Self-Assembled Superhydrophilic Polymer Membranes for Size-Exclusion Separation
Here we report a simple and roll-to-roll compatible bottom-up technology for continuously fabricating macroporous polymer membranes with highly uniform and 3-D interconnected nanopores for size-exclusion separation of viruses and bacteria from water. A vertically beveled doctor blade is utilized to shear-align colloidal silica suspensions to form large-area colloidal crystals with high crystalline qualities. The thickness of the shear-aligned crystals can be easily tuned by adjusting the concentration of the colloidal suspensions and the coating speed. The self-assembled colloidal crystals can then be used as structural templates in making self-standing macroporous polymer membranes. The large voids templated from colloidal particles are interconnected through much smaller nanopores that originate from the touching sites of particles. The high porosity of the resulting membranes enables the achievement of superhydrophilic surface with an apparent water contact angle of less than 5°, promising for high-flux filtration. In addition, by using appropriate polymers, the templated macroporous films can effectively reduce bio-fouling.