(386c) Remote Performance Modulation of Ultrafiltration Membranes By Magnetically and Thermally Responsive Polymer Chains
AIChE Annual Meeting
2020
2020 Virtual AIChE Annual Meeting
Separations Division
Surface Engineered and Responsive Membranes
Monday, November 16, 2020 - 8:15am to 8:30am
In an oscillating magnetic field, the tethered superparamagnetic nanoparticles can cause movement of the grafted PNIPAm chains or induce heating. A 20 Hz oscillating magnetic field maximizes movement of the grafted PNIPAm chains. For PNIPAM chains grafted from the outer membrane surface movement of the grafted polymer chains leads to break up of the concentration polarization boundary layer. This results in an increase in the observed rejection of partially rejected BSA. A 1000 Hz oscillating magnetic field leads to greater induced heating. PNIPAm displays a lower critical solution temperature (LCST) at 32 °C. Since the heat is generated at the interface with the PNIPAm chains heating leads to dehydration and collapse of the PNIPAm chains above their LCST. For PNIPAm grafted from the inner pore surface an increase in water and BSA flux is observed as well as a decrease in BSA rejection due to collapse of the chains. This work highlights the versatility of selectively grafting polymer chains containing a superparamagnetic nanoparticle from specific membrane locations. Depending on the frequency of the oscillating external magnetic field membrane properties may be tuned for a specific separation.