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28 p3ht - poly(3-hexylthiophene)Figure 2.12.: S(q) for 010 and 100 surfaces relaxed at 1 K and at roomtemperature.associated to a contemporary twisting of the structure thattends to assume a spherical shape in order to minimize thesurface energy (see Figure 2.15).Figure 2.14 and Figure 2.15 show the initial and final configurationsof two P3HT nanocrystals of size hxs of 16x16and 4x16 respectively. In the insets, the structure of the 010surfaces are shown together with the actual interdigitationdistance decrease. In the same figures the structure factorsS(q) along the y direction (the interdigitation direction) arereported before and after the relaxation. The S y peaks arelower than those of an ideal s-crystal, confirming the increaseof disorder and they shift toward higher q values,attesting the reduction in the interdigitation distance.2.6 conclusionsThe present analysis provides evidence that severe changesof lattice parameters and morphology are expected for finitesize polymers nanocrystals. This must be taken into