Surface Segregation of Small Macrocyclic

Surface segregation of the thin film blends containing 20wt{\%} 2k macrocyclic polystyrene were studied using surface MALDI-ToF mass spectrometry (MS), time of flight secondary ion mass spectrometry (ToF-SIMS), and neutron reflectometry (NR). To provide contrast between the species for these techniques, the linear polymer in the blend was deuterated. MALDI-ToF MS results show that the 2k macrocyclic chains are depleted from the surface after a film of an isotopic macrocylic/linear blend (h-CPS2K/ d-LPS2K) is annealed at 125$^{\circ}$C for 12hrs. The surface concentration of CPS is less than 1wt{\%}, while the surface concentration of the hydrogenous component in an analogous h-LPS2K/ d-LPS2K film is 20wt{\%} after annealing. The isotopic effect is not significant for the 2k blends and the architecture effect determines the surface segregation. ToF-SIMS and NR results corroborate this view.