Molecular Dynamics Modeling of Tubular Aluminum Silicate:  Imogolite

Abstract

The molecular models of tubular aluminumsilicate, imogolite, and tubular gibbsite for the comparison with imogolite were investigated by means of molecular dynamics simulations. The stability of these two models was tested in terms of the tube radii. It was shown that the total energy of tubular gibbsite is decreasing monotonically with the increasing radius of the tube. On the contrary, the total energy of imogolite has the minimum around diameter 2.6−2.9 nm. The details of the imogolite stability were inspected in terms of atom potential energy and the structural details.

Clay Mineral Nanotubes: Stability, Structure and Properties

“…Several theoretical studies (Tamura & Kawamura, 2002;Konduri et al, 2006;Alvarez-Ramirez, 2007;Guimaraes et al, 2007;Zhao et al, 2009;Demichelis et al, 2010;Lee et al, 2011) using different methodologies indicated that there is clearly a minimum in the strain energy curve of the imogolite. However, the minimum value is still a matter of controversy.…”

“…The first theoretical assessment on NT stability was carried out in the framework of molecular dynamics simulation using a classical many-body potential (Tamura & Kawamura, 2002) with specific parameters for imogolite. The total energy obtained with this method has the minimum strain energy per atom around a tube diameter of 2.6-2.9 nm, which means 16 gibbsite units around the circumference.…”

“…Imogolite is the most representative species of this case, since it has been studied in a pre-nano (1970) decade (Cradwick et al, 1972) and has been nearly forgotten until recently. Since 2000 (Bursill et al, 2000;Tamura & Kawamura, 2002;Mukherjee et al, 2005;Nakagaki & Wypych, 2007), these structures gained again prominence in the literature and appear as an emerging field of research. They can be used as nanoreactors for selective catalysts, adsorbent, nanocable, support for the immobilization of metalloporphyrins, encapsulation and ionic conductor (Nakagaki & Wypych, 2007;Kuc & Heine, 2009).…”

“…The first theoretical investigations on the aluminosilicate NTs were mostly based on force fields specially developed for these systems (Tamura & Kawamura, 2002). The size of the unit cell is normally a limitation for using quantum mechanical calculations.…”

Synthesis and Characterization of Fe-Imogolite as an Oxidation Catalyst

“…Recently, imogolite has drawn a new attention as a new nano-material because of its unique nano-scale tubular structure similar to that of a single-walled carbon nanotube [3]. Studies on synthesis [4][5][6][7][8][9], mechanisms of formation [10], structural evolution [11,12], stability [13,14], electronic states [14,15] and application have been carried out. Proposed applications, such as a polymer composite [16,17], a fuel gas storage [18], an absorbent [19], an exchange material for heat pump system [20], a humidity-controlling material [6] and an antideweling material [6] have been discussed.…”