A new wet chemistry approach, based on low-temperature (360 °C) decomposition in oleylamine of single-source precursors containing both metal and sulfur, is proposed for the production of stable free-standing nanosheets of MoS2 and WS2. The one-pot synthesis permits high-quality 2D nanosheet crystals of MoS2 and WS2 to be obtained with a modular number of nanolayers for units. The layered materials obtained are covered by a dynamic protective coating of oleylamine that stabilizes the suspension, avoids aggregation and oxidation phenomena, and could be easily functionalized with other molecules or nanosystems to introduce new properties to the hybrid organic–inorganic nanocomposite. The reaction products were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), attenuated total reflectance Fourier transform infrared spectroscopy (ART-FTIR), field emission scanning electron microscopy (FESEM), X-ray photoelectron spectroscopy (XPS), thermogravimetric analysis coupled with mass spectrometry (TG-MS), and dynamic light scattering (DLS) for particle size distribution (PSD).

No abstract

The empty space in different crystalline and clathrate phases of syndiotactic polystyrene (s-PS) is evaluated by a numerical procedure. It is shown that the δ form is nanoporous and includes two identical cavities per unit cell, whose shape and volume are characterized. As a consequence of clathration, the unit cell of the δ form is enlarged and the cavity is able to include molecules definitely larger than its starting size. Sorption experiments of nitrogen at 77 K for s-PS powders in different crystalline forms are also presented. These can be interpreted by inclusion of three nitrogen molecules per cavity of the δ crystalline phase and hence give an independent estimate of its volume.

No abstract

No abstract