Quantitative Scrolling into Microporous Nanotubes of the Hydrous Layered Silicate Ilerite

The synthetic hydrous layered silicate ilerite was quantitatively converted into microporous nanoscrolls (NS). Delamination of ilerite that was ion-exchanged for N-Methyl-D-glucaminium (Meg+), through one-dimensional (1D) dissolution initially yields lamellar liquid crystalline (nematic) suspensions. Subsequent protonation with acetic acid of tangling Si-O- to silanol groups reduces the pH-dependent charge of the basal surfaces. Complete NS formation is then triggered by diluting the nematic suspension below 0.05 wt%. As scrolling commonly has been attributed to hydrophobic interaction of organic counterions, Meg+ was replaced by lithium ions but this showed no detrimental effect on the scrolling efficiency. The resulting NS have a typical length of 2-4 mu m that corresponds well with typical diameters of the parent nanosheets. Ar-physisorption isotherms showed a bimodal micropore size with maxima around 0.8 and 1.9 nm. We attribute the first to the tubular hollow inner diameter of the NS and the latter to wedgelike interparticle porosity. The material showed a large specific surface area of 226 m2 g-1. image