2 research outputs found
Computer simulation of molecular shape transitions in adsorbed polymers under confinement conditions
The structural and dynamical properties of polymer-covered surfaces under confinement
and crowding effects are key to many applications. Earlier work showed the occurrence of
“escape transitions” in small uncompressed clusters (or “islands”) even for repulsive polymers.
These transitions involve a switch from evenly-compact configurations (“trapped chains”), to
uneven compactness (“escaped chains”). Here, we address a complementary question: if the
crowding is reduced by having fewer neighbours, can an external compression produce “escaped
configurations”? To this end, we focused on the confinement of grafted polymers. At low
compression, the inter-chain entanglement increases with excluded volume as chains swell and
interpenetrate, up to a critical chain length where the behaviour is reversed. We conclude that,
when few chains are present or if a larger ensemble of them is arranged symmetrically,
compression induces chain avoidance without inducing escape transitions. The switch in
mechanism depends mostly on crowding, and not on the applied pressure.Master of Science (MSc) in Chemical Science