A novel aromatic diamine monomer bearing tertbutyl and 4-tertbutylphenyl groups, 3,3′-ditertbutyl-4,4′-diaminodiphenyl-4′′-tertbutylphenylmethane (TADBP), was prepared and characterized. A series of non-coplanar polyimides (PIs) were synthesized via a conventional one-step polycondensation from TADBP and various aromatic dianhydrides including pyromellitic dianhydride (PMDA), 3,3′,4,4′-biphenyltetracarboxylic dianhydride (BPDA), 4,4′-oxydiphthalic anhydride (OPDA), 3,3′,4,4′-benzophenone tetracarboxylic dianhydride (BTDA) and 4,4′-(hexafluoroisopropylidene)dipthalic anhydride (6FDA). All PIs exhibit excellent solubility in common organic solvents such as N,N-dimethylformamide (DMF), N,N-dimethylacetamide (DMAc), N-methyl-2-pyrrolidone (NMP), dimethyl sulfoxide (DMSO), chloroform (CHCl3), tetrahydrofuran (THF), and so on. Furthermore, the obtained transparent, strong and flexible polyimide films present good thermal stability and outstanding optical properties. Their glass transition temperatures (Tgs) are in the range of 298 to 347°C, and 10% weight loss temperatures are in excess of 490°C with more than 53% char yield at 800°C in nitrogen. All the polyimides can be cast into transparent and flexible films with tensile strength of 80.5–101 MPa, elongation at break of 8.4%–10.5%, and Young's modulus of 2.3–2.8 GPa. Meanwhile, the PIs show the cutoff wavelengths of 302–356 nm, as well as low moisture absorption (0.30% –0.55%) and low dielectric constant (2.78–3.12 at 1 MHz).
A polyhedral oligomeric silsesquioxane (POSS)-based supramolecular amphiphile is prepared from the host–guest inclusion complexation between a mono adamantane-functionalized POSS (AD-POSS) and a β-cyclodextrin oligomer (P(β-CD)). Assisted by the interface of H2O/toluene, the obtained supramolecular hybrids self-assemble into stable hollow nanospheres with thick walls. These hollow nanospheres aggregate together into a sphere layer through a spin coating technique, which then further transforms into a thin porous film containing nanometer-scale holes. The hollow nanospheres have a low cytotoxicity. The in vitro cell culture indicates the nanoporous films promote adhesion and proliferation of cells. The self-assembly morphologies and structures have been carefully characterized by SEM, TEM, AFM, DLS, XPS and water-contact angle measurements, and the self-assembly mechanism has also been discussed.
