Porous Poly(Acrylic Acid) from High Internal Phase Emulsion: Effects of Emulsification Parameters on Porous Structure

Highly porous poly (acrylic acid) (P(AA)) with tunable pore structure was prepared through polymerizing of acrylic acid in the aqueous phase of an oil-in-water (O/W) high internal phase emulsion (HIPE). Compared with the conventional O/W HIPE normally using toluene or hexane as internal phase, the introducing paraffin, which have a much higher viscosity than toluene or hexane, caused the HIPEs herein could be stabilized by Tween 60 of low to 0.5 wt%. It was found the amount of liquid paraffin played a key role for the stability of the emulsion and the morphology of the resulting porous materials. Moreover, the average void size and the interconnectivity degree of the porous materials could also be tailored by altering the acrylic acid and surfactant concentration in aqueous phase