Fabrication of porous poly(acrylamide) beads with macro- and micropores

On the basis of an oil-in-water-in-oil emulsion, polyacrylamide (PAM) beads with a dual porous structure were fabricated using both an emulsion and polystyrene (PS) particles as templates. Uniform oil-in-water droplets dispersed in an oil phase (a sedimentation medium) were polymerized in a reaction glass column, where the water phase contained acrylamide and PS particles. Afterward, the cross-linked PAM beads were immersed in n-hexane and methanol to remove all of the oil phases and then in acetone and toluene to remove the PS particles, resulting in dual porous PAM beads. The PAM beads exhibited macropores (5-30 μm) and micropores (approximately 400 nm) that were developed by the removal of the inner oil phase and the PS particles, respectively. The employment of PS particles as templates resulted in a remarkable increase in the pore area from 2.2 to 6.3 m ²/g. In addition, an increase in the volume ratio of the inner oil phase to the water phase for the primary oil-in-water emulsion led to an increase in the pore volume and a reduction in the pore area. POLYM. ENG. SCI., 2012.