The morphology of samples obtained from the FeClTPP mixture

The morphology of samples obtained from the FeClTPP mixture (Fig. 3b), is characterized by a significantly greater non-uniformity of the surface on which inclusions of larger crystallites are observed, while columnar structures are absent. Since we assume that different types of iron porphyrins (containing both chlorine and oxygen in one form or another) coexist in this film, the observed crystal structures may correspond to different phases of the same compound. The common feature of these two types of samples is the formation of a solid film with a relatively smooth surface. A fundamentally different structure is observed when examining the CuTPP film surface. The films obtained under identical processing conditions self-assemble into crystalline nanowires of about 20nm in thickness and up to 5µm in length (Fig. 4a). It should be noted that the authors of Ref. [11], who studied the structure of CuTPP films obtained by conventional thermal evaporation (i.e., in the absence of quasi-equilibrium conditions), obtained a disordered nanocrystalline structure with an average crystal size of about 60nm, with no specific nanowires or nanorods found. To compare the structures and anisotropy of CuTPP condensates prepared by gas-phase evaporation from solution, we examined, using scanning iap apoptosis microscopy, CuTPP porphyrin films on silicon substrate prepared by crystallization from solution (casting), i.e., by slow evaporation from solution in C6H5CH3 toluene (Fig. 4b). These crystals also exhibit a pronounced anisotropy and form from nanorods of about 1µm in diameter and about 10µm in length; however, it should be kept in mind that porphyrin molecules are always solvated by solvent molecules under crystallization from solution, so the crystalline phases can differ significantly.
Conclusions We studied for the first time the structure of films and the processes of their self-assembly during CuTPP crystal growth which result through crystallization under quasi-equilibrium conditions in the formation of non-oriented porphyrin nanowires of about 20nm in diameter and up to 5µm in length. The films of other metalloporphyrins we have studied have a coarse crystalline structure (crystallite sizes range from 1 to 5µm) with a high crystal density without a pronounced anisotropy.
Introduction The polymer crystals are formed from the stretched parts of chain molecules stacked parallel along the direction of the orienting force [1]. The linear size of these parts ranges from 20 to 100 nm [2], so, these crystalline objects are nanocrystals. Their distinctive feature is the sharp anisotropy of mechanical and thermal properties in the longitudinal (along the axes of stretched molecules) and in the transversal (orthogonal to the molecular axes) directions. E.g., the rigidity of crystalline lattice and the characteristic temperatures of vibrations are substantially higher in longitudinal direction than in transversal one [3]. This fact determines certain features of the deformation response of the polymer crystals to mechanical and thermal effects. Moreover, the chain structure of macromolecules leads to specific types of stiffness of polymeric material: the stretching hardness (an increase in contour length of molecules) and flexural rigidity (the ``curvature\'\' change of segments of chain molecules, leading to a change in its axial length). However, despite the large number of studies [1] considering the description of the polymer nanocrystal deformation response to the mechanical (stretching) and thermal (heating) effects, a number of issues need further clarification. In particular, the behavior details of skeletal interatomic bonds of macromolecular segments forming nanocrystals when subjected to the actions mentioned remain unclear. To obtain the necessary information it is advisable to use such methods to study molecular dynamics as diffraction (X-ray, electron, neutron) and Raman spectroscopy. The latter is known to be sensitive to the influence of various effects on the skeletons of polymeric molecules [4,5]. The combination of Raman and X-ray methods of investigation leads to a clarification at the molecular level of the mechanics and energetics of polymer nanocrystals subjected to these conditions.