Thermodynamics and ordering kinetics in asymmetric PS-b-PMMA block copolymer thin films. Issue 23 (5th June 2020) - Seguini, Gabriele
Abstract : The coupling between kinetics and thermodynamic driving force of standing cylinder-forming PS- b -PMMA BCPs on flat and unpatterned surface is investigated following the time evolution of the correlation length at different annealing temperatures. Abstract : The ordering kinetics of standing cylinder-forming polystyrene- block -poly(methyl methacrylate) block copolymers (molecular weight: 39 kg mol −1 ) close to the order–disorder transition is experimentally investigated following the temporal evolution of the correlation length at different annealing temperatures. The growth exponent of the grain-coarsening process is determined to be 1/2, signature of a curvature-driven ordering mechanism. The measured activation enthalpy and the resulting Meyer–Neldel temperature for this specific copolymer along with the data already known for PS- b -PMMA block copolymers in strong segregation limit allow investigation of the interplay between the ordering kinetics and the thermodynamic driving force during the grain coarsening. These findings unveil various phenomena concomitantly occurring during the thermally activated ordering kinetics at segmental, single chain, and collective levels.