Computational modelling of emergent out-of-equilibrium phenomena in branched polymers
Polymers are long molecules that can be built like strings, stars, or bottlebrushes. By changing their shape, we can make materials that are tougher, softer, or flow more easily. In his thesis, Utku Gürel looks at how different polymer shapes behave under challenging conditions such as stretching, impact, being trapped in a network, or mixing with charged molecules. Using computer simulations and experiments, Gürel found new ways to improve material performance without changing the basic chemistry.
For example, in thin polymer films, mixing short and long branches in the same molecule made the films up to 4.5 times tougher while keeping them just as stiff, ideal for protective coatings. In another study, Gürel showed that how bottlebrush-shaped polymers flow depends on the small-scale arrangement of their bonds, not just their overall shape. Gürel also found that the way polymer nanoparticles move inside a soft network can be predicted from their earliest tiny vibrations, and that their shape decides whether they move smoothly or in a stop-and-go fashion.
Finally, Gürel discovered that in mixtures of charged star-shaped and chain-shaped polymers, the chains can connect several stars, sometimes causing the material to separate into two distinct layers. These results show that by carefully designing a polymer’s shape and size, we can fine-tune how it behaves. This opens the door to better coatings, flexible electronics, medical gels, and more.