Figure 2.

(a) The mapping scheme from all-atomistic model to the three-bead per monomer coarse-grained model for P3HT (left); schematic illustration of polymer thin film (right). (b) T-dependent segmental relaxation time τ_seg for 10 nm- and 30 nm-thick films comparing with the bulk system at various K_rigidity values. The solid and dashed curves represent the VFT fits of the τ_seg data. (c) The distribution of local τ_seg as a function of film position z for different K_rigidity values. (d) Distribution of local molecular stiffness 1/⟨u²⟩ as a function of film position z for different K_rigidity values. (e) Color maps of the 1/⟨u²⟩ for the interior layer and surface layer with varying K_rigidity. The red domains correspond to lower local stiffness or higher local mobility, while blue domains correspond to higher local stiffness or lower local mobility. The color map scale is the same for all images (color online).