(797f) Understanding Retention of Block Copolymers in Size Exclusion Chromatography and Liquid Chromatography At the Critical Condition

Chromatographic separations involve a delicate interplay of enthalpic and entropic factors arising from interactions of the analyte molecules with the stationary and mobile phases. Particle-based simulations allow one to probe chromatographic systems on the molecular level and to provide detailed information on structural characteristics and retention mechanisms.  This talk will highlight recent applications of configurational-bias Monte Carlo simulations in the Gibbs ensemble to understand the retention mechanisms of block copolymers in size exclusion chromatography (SEC) and in liquid chromatography at the critical condition (LCCC) for one of the blocks.  Copolymers with up to three block types and up to five blocks are investigated.  It is found that sequence and architecture play a major role in determining retention order of copolymers with identical composition.  Structural analysis of the simulation trajectories provides and explanation for the retention order.