@article{bhattacharya_coasne_hung_gubbins_2009, title={Modeling Micelle-Templated Mesoporous Material SBA-15: Atomistic Model and Gas Adsorption Studies}, volume={25}, ISSN={["0743-7463"]}, DOI={10.1021/la801560e}, abstractNote={We report the development of a realistic molecular model for mesoporous silica SBA-15, which includes both the large cylindrical mesopores and the smaller micropores in the pore walls. The methodology for modeling the SBA-15 structure involves molecular and mesoscale simulations combined with geometrical interpolation techniques. First, a mesoscale model is prepared by mimicking the synthesis process using lattice Monte Carlo simulations. The main physical features of this mesoscale pore model are then carved out of an atomistic silica block; both the mesopores and the micropores are incorporated from the mimetic simulations. The calculated pore size distribution, surface area, and simulated TEM images of the model structure are in good agreement with those obtained from experimental samples of SBA-15. We then investigate the adsorption of argon in this structure using Grand Canonical Monte Carlo (GCMC) simulations. The adsorption results for our SBA-15 model are compared with those for a similar model that does not include the micropores; we also compare with results obtained in a regular cylindrical pore. The simulated adsorption isotherm for the SBA-15 model shows semiquantitative agreement with the experimental isotherm for a SBA-15 sample having a similar pore size. We observe that the presence of the micropores leads to increased adsorption at low pressure compared to the case of a model without micropores in the pore walls. At higher pressures, for all models, the filling proceeds via the monolayer-multilayer adsorption on the mesopore surface followed by capillary condensation, which is mainly controlled by the mesopore diameter and is not influenced by the presence of the micropores.}, number={10}, journal={LANGMUIR}, author={Bhattacharya, Supriyo and Coasne, Benoit and Hung, Francisco R. and Gubbins, Keith E.}, year={2009}, month={May}, pages={5802–5813} }
 @article{hung_bhattacharya_coasne_thommes_gubbins_2007, title={Argon and krypton adsorption on templated mesoporous silicas: molecular simulation and experiment}, volume={13}, ISSN={["1572-8757"]}, DOI={10.1007/s10450-007-9034-4}, number={5-6}, journal={ADSORPTION-JOURNAL OF THE INTERNATIONAL ADSORPTION SOCIETY}, author={Hung, Francisco R. and Bhattacharya, Supriyo and Coasne, Benoit and Thommes, Matthias and Gubbins, Keith E.}, year={2007}, month={Dec}, pages={425–437} }
 @article{bhattacharya_gubbins_2006, title={Fast method for computing pore size distributions of model materials}, volume={22}, ISSN={["0743-7463"]}, DOI={10.1021/la052651k}, abstractNote={Recently developed atomistic models of highly disordered nanoporous materials offer hope for a much more realistic description of the pore morphology and topology in such materials; however, a factor limiting their application has been the computationally intensive characterization of the models, particularly determination of the pore size distribution. We report a new technique for fast computation of pore size distributions of model materials from knowledge of the molecular coordinates. The pore size distribution (PSD) is defined as the statistical distribution of the radius of the largest sphere that can be fitted inside a pore at a given point. Using constrained nonlinear optimization, we calculate the maximum radii of test particles at random points inside the pore cavity. The final pore size distribution is then obtained by sampling the test particle radii using Monte Carlo integration. The computation time depends on factors such as the number of atoms, the sampling resolution, and the desired accuracy. However, even for large systems, PSDs with very high accuracy (>99.9%) are obtained in less than 24 h on a 3 GHz Pentium IV processor. The technique is validated by applying it to model structures, whose pore size distributions are already known. We then apply this method to investigate the pore structures of several mesoporous silica models such as SBA-15 and mesostructured cellular foams.}, number={18}, journal={LANGMUIR}, author={Bhattacharya, Supriyo and Gubbins, Keith E.}, year={2006}, month={Aug}, pages={7726–7731} }
 @inproceedings{bhattacharya_coasne_hung_gubbins_2006, title={Modeling triblock surfactant templated mesoporous silicas (MCF and SBA-15): A mimetic simulation study}, volume={160}, DOI={10.1016/s0167-2991(07)80068-1}, abstractNote={We have developed models for templated mesoporous silicas such as Mesostructured Cellular Foams and SBA-15. The first part of our work elaborates the effect of oil concentration on the pore morphology of the triblock surfactant templated mesoporous materials. Our Lattice Monte Carlo simulations mimic the synthesis process by equilibrating a mixture of triblock surfactant, oil, water and silica at a constant temperature and density. With increasing oil concentration, we find the pore geometry to change according to the sequence: cylinders → lamellae → mesocells, which is in qualitative agreement with experimental results. In the second part of our work, we develop realistic atomistic models of the SBA-15 material, starting from the mesoscale model obtained from Lattice Monte Carlo simulations. Both the pore surface heterogeneity and the micropores are derived from the mimetic simulations. The simulated TEM and pore size distribution of the model qualitatively resemble the real material.}, booktitle={Characterization of porous solids vii - proceedings of the 7th international symposium on the characterization of porous solids (cops-vii), aix-en-provence, france, 26-28 may 2005}, author={Bhattacharya, S. and Coasne, B. and Hung, F. R. and Gubbins, Keith}, year={2006}, pages={527–534} }
 @article{bhattacharya_gubbins_2005, title={Modeling triblock surfactant-templated mesostructured cellular foams}, volume={123}, ISSN={["1089-7690"]}, DOI={10.1063/1.2013250}, abstractNote={Lattice Monte Carlo simulations are used to understand the role of surfactant self-assembly in the synthesis of templated mesoporous materials with ultralarge pores. Our system consists of model triblock surfactants in the presence of oil, water, and inorganic oxide. Depending on the temperature and component concentrations, these systems phase separate, and the surfactant-rich phase forms structures such as cylinders, lamellae, and spheres ordered in repetitive arrangements. In the absence of oil, the structures are cylindrical with diameters of 100 A, but increasing oil concentration produces ultralarge spheres with diameters above 500 A. Our results closely resemble the cylinder to sphere transition associated with the synthesis of the mesostructured cellular foams (MCFs). Pore size distributions of our model structures are qualitatively comparable with the pore size distributions of MCFs obtained from adsorption experiments. We also observe an increase in average pore size with oil concentration, which is consistent with the experimental reportings.}, number={13}, journal={JOURNAL OF CHEMICAL PHYSICS}, author={Bhattacharya, S and Gubbins, KE}, year={2005}, month={Oct} }