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The development of cost-effective technologies to efficiently capture and store CO2 can help towards the reduction of greenhouse gases to the atmosphere, as well as to improve the efficiency of processes in the petrochemical industry that rely on these separations. The aim of this project is to develop computational procedures for optimizing the structure of polymers for use in adsorption-based separations, and hence to generate a polymer-based porous material with significantly higher selectivity and capacity for carbon dioxide adsorption than materials currently available.

      Polymers of Intrinsic Microporosity (PIMs) are a novel class of porous polymer with potential application in storage, separations, and purification.  In PIMs, functionality can be directly embedded in the material framework. PIMs are disordered materials, but the chemistry of the framework is well controlled and therefore PIMs can have some of the advantages that disordered materials have while maintaining control at a nanometer scale by knowing precisely the structure and chemistry of the monomers. The general structural scheme of PIMs is to connect rigid backbone segments by non-linear or non-planar sites of contortion, which allows for a wide range of chemistries and resultant materials.

            As mentioned in the first year report, a consequence of the results obtained so far, we believed it was necessary to perform a detail study of the charges in the monomer, and thus to improve the force-field to be used, especially near the flexible diether (or diamine) ring and the spiro-center. Even though quantum mechanics calculations are demanding, they were necessary to include in this project for the generation of a truly realistic monomer. This task was not originally planned, and although time consuming, was crucial for the next steps of the structure generation and adsorption experiments. This was the focus of the second year of this project.

      During the NCE period we will determine, via grand canonical Monte Carlo (GCMC) simulations, adsorption isotherms and heats of adsorption. To understand the morphological and dynamical properties of PIM-1, and PIM-1 like structures, we aim to develop a model that is sufficient to recover basic quantitative aspects of absorbents in real PIMs, to be in a position to investigate the effect of some of the variables that are expected to be relevant for these systems, and thus guide the synthesis on new PIMs. Despite the complexity of PIM-1 the simulation results demonstrate the effectiveness of our model when compared to experimental data.  The simulations predict CO2 uptake in qualitatively agreement with experimental results. However, the calculated adsorption capacity over predicts the experimental observed values by a factor of 2.

      This PRF grant has supported a graduate student (Mr. Gregory Larsen) and an undergraduate student (Mr. Wai Fong Chan). In addition, funding by the PRF enabled us to obtain a sufficient amount of preliminary data on this project, instrumental for securing continuous funding from the National Science Foundation. 

      In this project, graduate and undergraduate students are gaining experience in modeling advanced functional porous materials. Graduate students have presented the results of their research at national and international conferences (highlighted in bold below). Finally, the originally proposed research is still subject of ongoing investigations and is expected to result in at least two future publications that will acknowledge PRF support. So far, we have presented our results at several conferences:

1. Larsen, G. S., Lin, P, and C. M. Colina, “Simulated Adsorption and Characterization of Novel Nanoporous Polymers,” AIChE National Meeting, Salt Lake City, (2010).

2. Colina, C. M. “Novel Nanoporous Polymers: Molecular Modeling,” XIX International Materials Research Congress, invited, Cancún, México, (2010).

3. Cataño-Barrera, A. M., Siquier-Soler, S., and C. M. Colina, “Separation of Polymers by Supercritical Carbon Dioxide,” XIX International Materials Research Congress, Cancún, Mexico (2010)

4. Larsen, G. S., Lin, P, and C. M. Colina, “Grand Canonical Monte Carlo Simulations of Adsorption of Carbon Dioxide and Methane in Regular and Carbonyl Substituted PIM-1,” Macro 2010, Glasgow, U.K., (2010).

5. Cataño-Barrera, A. M., Siquier-Soler, S., and C. M. Colina, “Separation of Polymers by Supercritical Carbon Dioxide,” Graduate Women in Science National Meeting, State College, (2010).

6. Larsen, G. and C. M. Colina,  “Exploring New Materials for Gas Storage and Separations: Molecular Simulations of Polymers of Intrinsic Microporosity” Polymer Physics Gordon Research Conference, Mount Hyoloke (2010)

7. Larsen, G. S., Siperstein, F. R. and C. M. Colina. “Exploring New Materials for Gas Storage and Separations: Molecular Simulations of Polymers of Intrinsic Microporosity” Fundamental of Adsorption, Awaji, Japan, (2010).

Submitted publications:

1. Larsen, G. S., Lin, P., Siperstein, F. R. and C. M. Colina, “Methane Adsorption in PIM-1,” Adsorption, submitted (2010).

2. Castro-Marcano, F., Cataño-Barrera A. and C. M. Colina “Phase Behavior of Polymer Solutions from Macroscopic Properties: Application to the PC-SAFT Equation of State,” submitted, Ind. Eng. Chem. Res. (2010).