Molecular dynamics (MD) calculations of clusters with up to 184 molecules of decane (DC/184), eicosane (ES/128) and the perfluorinated (PFDC/184, PFES/128) and semi-fluorinated (SFES/128) analogs have been performed using the AMBER 5 program. The aim was to investigate the different behaviour of alkanes and fluorinated alkanes in the process of molecular aggregation. Moreover, mixed clusters of decane and perfluorodecane (DC/92 + PFDC/92) with different starting configurations have been studied. The flexibility of the chains and the influence of structure formation in the clusters as well as the tendency for microphase separation in the mixtures have been analysed using snapshots, radial atom pair distribution functions, orientational correlation functions and diffusion coefficients.