Physico-Chemical nanomaterials science
Two-dimensional crystal structure formed by chain molecules in the pores of a solid matrix
K.I. Hnatiuk1, A.N Alekseev1, S.A. Alekseev1, Yu.E. Grabovsky1, M.M. Lazarenko1, Yu.F. Zabashta1, R V. Dinzhos2, L.A. Bulavin1
1 Taras Shevchenko National University of Kyiv, Physical Faculty, Volodymyrs’ka St. 64/13, Kyiv 01601, Ukraine.
E-mail: email.of. corresponding_20gnatk@gmail.com
2 Mykolayiv NationalUniversity named after V.O.Sukhomlynskiy, 24, Nikolska Str., 54030 Mykolayiv, Ukraine
For the statistical description of the arrangement of particles constituting the system, a density function is introduced , where x, y, z are the coordinates of the particle. For crystals, it is a triple-periodic function with periods equal to the periods of the crystal lattice. It is also possible the existence of systems for which the density function depends on two coordinates . This function corresponds to a two-dimensional crystal structure in which the particles are arranged in a random manner along lines parallel to the Z axis. This function is doubly periodic: the points of intersection of these lines with the plane perpendicular to the Z axis form a two-dimensional lattice.
Located in the pores of a solid matrix, chain molecules can form both a two-dimensional and a three-dimensional crystalline structure, which they form in a large volume. The two-dimensional structure differs from the three-dimensional structure in that the periodicity in the direction of the crystallographic axis disappears along which the chains are oriented - the latter are shifted relative to each other in a random manner, while in the direction of the remaining crystallographic axes the periodicity is conserved.
In this work, the investigation of two-dimensional crystal structures formed by chain molecules in the pores of a solid matrix is continued. X-ray diffraction patterns of silicon and porous silica gel containing 1-octadecene in their pores were obtained.
It was found that 1-octadecene in silicon pores has a three-dimensional crystalline structure, and in the pores of silica gel has a two-dimensional crystal structure. The mechanism of formation of such a structure is proposed.