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Soroush Moghadam

soroush Contact Information
Email soroushm@umich.edu
Phone 734.936.1381
Office 010 G049F NCRC, Biointerfaces Institute
University of Michigan, Ann Arbor, MI 48105
B. S. Mechanical Engineering, University of Tehran, Tehran, Iran (2014).

Current Research

Rheology of entangled polymers

The idea that the dynamics of concentrated, high-molecular weight polymers are largely governed by entanglements, or in other words, constraints, is now widely accepted and typically understood through different models such as tube model. A simulation approach to include these entanglements in the dynamics of a single chain is the use of slip-links or additional potential fields around the main polymer chain to limit the spatial availability and affect the stress relaxation properties. We analyze the constraint release mechanism and its influence on the dynamics of polymeric fluids in equilibrium and under flow. The flow behavior of polymeric liquids is of supreme interest, particularly for industry, for which the optimization of polymer-processing conditions is necessary to achieve a high throughput with low consumption of energy and materials.

Figure 1. Mathematical modeling of a single entangled chain in a polymeric fluid

Assessing the efficiency of poly N-isopropylacrylamide (pNIPAAm) in drug delivery applications

Thermo-sensitive polymers are being widely examined for potential drug delivery applications. These macromolecules undergo a drastic change in properties by changing the temperature. pNIPAAm becomes insoluble in water when the solution is heated up above 32oC, close to body temperature. This LCST behavior near the physiological condition of human body has made pNIPAAm a very attractive polymer for solid dispersions used for controlled release properties of hydrophobic drugs. Through molecular dynamics simulations, we analyze the interactions between pNIPAAm oligomers and Phenytoin (as a hydrophobic drug) and try to tune polymer properties to achieve higher drug molecules’ dispersion. The lower the drug molecules interact with each other, the lower the crystal nucleation probability will be, which consequently results in a better controlled drug release.

Figure 2. Radius of gyration of a 26-mer single pNIPPAm chain as a function of temperature

Figure 3. Polymer chains and drug molecules (red) interacting with each other in water. Water molecules are not shown.