S.D. Hopkins, E. Blaisten-Barojas
George Mason University,
United States
Keywords: thermoresponsive polymers, PNIPAM, PDEA, molecular dynamics, lower critical solution temperature, LCST
Summary:
Thermoresponsive polymers have been utilized in a broad range of medical and industrial applications as smart materials, including controlled drug delivery, and water treatment and desalination. While the behavior of such polymers has been modeled in aqueous solutions, study of their behavior in viscous solvents is very limited. In this research, the thermoresponsive behavior of PNIPAM, poly(N-isopropylacrylamide)) and poly(N,N-diethylacrylamide) (PDEA) has been thoroughly evaluated using Molecular Dynamics techniques and the OPLS/AA force field. Structural and energetic properties including radius of gyration, solvent accessible surface area, and oligomer-solvent interaction energies were characterized. Simulation results indicate that these polymers sustained a reversible coil-to-globule transition in glycerol, with a significant increase in lower critical solution temperature (LCST) when compared to the collapse transition in aqueous solutions. These findings yield crucial insight into industrial applications where polymer phase behavior at higher LCST is advantageous. *Acknowledgment: Partial support from the Commonwealth of Virginia, grant 4VA, Scalable Molecular Dynamics