The morphology and phase shift of phase-separated PMMA/SAN thin film on silicon wafer were studied by in situ AFM with hot stage through the annealing and quasi-quenching. The results show that the phase shifts are different between high temperature and room temperature, and between ultrahigh vacuum and ambient and between in situ and ex situ although the morphologies are almost invariable. The reasons were discussed simply.
A bolaform amphiphile(BP-15) bearing biphenyl group and long spacers of alkyl chains was synthesized. In-situ AFM studies indicate that the amphiphile can form two kinds of surface aggregates with different morphologies depending on solution concentration: short-range ordered cylindrical surface micelles at the lower concentration and flat domains at the higher concentration. These results agree well with the two critical micelle concentrations in bulk solution as determined by the concentration-dependent conductivity.
We have described the synthesis of a series of poly(aryl ether) dendrimers with telluride in the core and oligo(ethylene oxide) chains at the pe- riphery which act as glutathione peroxidase (GPx) mimics. These series of compounds were well characterized by H-NMR, 1 13C-NMR and ESI-MS. Using different ROOH (H2O2, cumene hydroperoxide) for testing the antioxidizing properties of these com- pounds, we have found that from generation 0 to 2, the activity of the dendritic GPx mimics first de- creased and then increased. This can be explained on the basis of a greater steric hindrance, going from generation 0 to 1, and stronger binding interactions going from generation 1 to 2. In other words, there exists a balance between binding interactions and steric hindrance that may optimize the GPx activity.
