Unusual interfacial phenomena at a surface of fullerite and carbon nanotubes

- Interfacial behavior of polar and nonpolar adsorbates vs. structure of fullerite and MWCNT.
- Confined space effects on the characteristics of water bound to carbons.
- Broadening of 1H NMR spectra of water adsorbed to carbons toward strong downfield and upfield shifts.
- Strongly and weakly associated and strongly and weakly bound waters.
- Decreased activity of bound water as a solvent.

Interactions of water, methane, HCl, C6H6, F3CCOOD, and hyaluronic acid with fullerite C60/C70 and multi-walled carbon nanotubes (MWCNT) were studied in various media using 1H NMR spectroscopy. The materials were characterized using microscopy, differential scanning calorimetry, Raman spectroscopy, and quantum chemical methods. Water with weakly (WAW) and strongly (SAW) associated molecules bound to fullerite demonstrates unusual downfield shifts δH < 18 ppm. WAW in contrast to SAW cannot dissolve acids. Water bound to MWCNT demonstrates the downfield shift smaller than that observed for fullerite. Fullerite possesses low porosity due dense packing of fullerenes in molecular crystals. Therefore, noticeable adsorption is observed only for compounds, which are capable for intercalation (benzene, toluene, water), but nitrogen cannot be adsorbed by fullerite. For MWCNT with much looser structure than that of fullerite, pre-adsorbed water weakly affects methane adsorption. An increase in pre-adsorption of water results in decrease in adsorption of methane onto MWCNT.