Documento PDF - UniCA Eprints - Università degli studi di Cagliari.

40 polymer/semiconductor interfaceFigure 3.9.: Structure factor in the three crystallographic directionsfor the 010 HDR interface at low and room temperature.Figure 3.10.: Final configuration of the 010 HDR system at 300 K.the substrate. We found that in this interface model thepolymer is more disordered than in the 010 case and tendsto bend toward the surface in order to increase the interactionswith it (see Figure 3.11).As shown in top-middle panel of Figure 3.12, the interactionwith the substrate causes disorder in the π − π directionand gives a low peak in S y structure factor (we recallthat in this case the π − π channels are along y, parallel tothe ZnO surface). The average π − π distance is found toincrease from 4 to 4.8 Å. On the other hand, sharp peaksare present in S z (top-right panel of Figure 3.12) standingfor a high order in the interdigitation direction. The shift ofthe S z peak with respect to the s-crystal shows a strong reductionin the interchain distance, and corresponds to 12.5Å.