Molecular Modeling Applied to CO2-Soluble Molecules and Confined Fluids

摘要

CO2 is known to be an environmentally benign solvent. However, its feeble solvent power inhibits its wide use in industrial applications.The ultimate goal of this research is to design and optimize polymers that are highly soluble in CO2. Molecular modeling methods have been usedto analyze the results from experiments and make predictions. We have employed ab initio quantum mechanical methods to investigate interactions between CO2 molecules and polymers. This is done by computing the interactions between CO2 and polymer moieties and important functional groups. These functional groups include ether oxygens, carbonyl oxygens, and fluorines. We have identified several factors that believed to be responsible for CO2-philicity. These factors include multiple site bindings, acidic hydrogens,and geometric considerations. We have designed three possible CO2-soluble molecules based on our calculation results. Our experimental colleagues have synthesized and tested the corresponding polymers to compare with our predictions. Single wall carbon nanotubes have attracted significant scientific interest as adsorption media since their discovery. Fluids confined in nanotubes have significantly different behavior from bulk fluids. We have performed simulations for alkanes adsorbed in the internal and externalsites of carbon nanotubes. The simulation resultsqualitively match the experimental data from temperature programmed desorption. The diffusion coefficients in bulk and confined phases have been calculated. We have also studied the structure andinfrared spectra of water adsorbed in nanotubes over a wide range of temperatures. Our simulation studies have identified the essential physics responsible for a distinctive infrared band observed in recent experiments.