Self-rolling of an aluminosilicate sheet into a single walled imogolite nanotube: The role of the hydroxyl arrangement

Advancements in the Synthesis of Building Block Materials: Experimental Evidence and Modeled Interpretations of the Effect of Na and K on Imogolite Synthesis

“…For H-Imo, an energy minimum of N = 8 was obtained, which was very close to the N = 9 value. The diameter decreased within the range N = 8–12, similar to values previously reported. − We also adjusted the size of the box along the imogolite axis and obtained, for the length of the unit cell, 8.55 Å for N = 7 and 8.8 Å for N = 10, which were also quite close to other theoretical results in the literature that were between 8.40–8.84 Å and the experimental results of 8.4–8.5 Å. ,,,, …”

“…51−53 We also adjusted the size of the box along the imogolite axis and obtained, for the length of the unit cell, 8.55 Å for N = 7 and 8.8 Å for N = 10, which were also quite close to other theoretical results in the literature that were between 8.40−8.84 Å and the experimental results of 8.4−8.5 Å. 10,52,55,57,58 When replacing the H atoms in the inner wall of the NT by Na or K, the total energy increased, and the energy minimum was shifted to N = 11 and N = 18, respectively. Which meant that, first, the results were energetically more favorable for NTs with H than with Na or K as a final product of the synthesis, and second, we expected it to be less probable to obtain imogolite NTs using K than Na.…”

“…Classical Molecular Dynamics (MD) simulations with the Large-scale Atomic/Molecular Massively Parallel Simulator (LAMPS) code were used . The atomic interactions were modeled with the ReaxFF potential, parametrized against the interaction of the solute with organic molecules and tested. − We chose to use the Fast Inertial Relaxation Engine (FIRE) in combination with conjugate gradient minimizations to optimize the nanotube (NT) conformation and the length of the simulation cell, with encouraging results . The LAMMPS implementation of FIRE does not allow you to vary the length of the simulation box; however, it does implement conjugate gradients.…”

“…65−68 We chose to use the Fast Inertial Relaxation Engine (FIRE) in combination with conjugate gradient minimizations to optimize the nanotube (NT) conformation and the length of the simulation cell, with encouraging results. 55 The LAMMPS implementation of FIRE does not allow you to vary the length of the simulation box; however, it does implement conjugate gradients. On the other hand, FIRE yields lower energy structures.…”

Mechanical Response of Aluminosilicate Nanotubes under Compression

“…The main tool we use is classical molecular dynamics (MD) simulations. These MD simulations, as well as the structural relaxations, were carried out using the large-scale atomic/molecular massively parallel simulator (LAMMPS) code accelerated with the GPU package. − For the atomic interactions the CLAYFF potential is used, since it has been proven to be adequate to model aluminosilicate (imogolite) NTs. − ,− …”