GOALI: Collaborative Research: Development of transferable force fields and Monte Carlo algorithms and application to phase and sorption equilibria
The development of sustainable processes in the chemical and biotechnology industries and of novel formulations in the personal care and detergent industries is of tremendous commercial and environmental importance. Molecular-level knowledge is essential for moving from trial-and-error based approaches to knowledge-driven design of these chemical processes and formulations. To this extent, accurate molecular models and efficient simulation algorithms will be developed by a collaborative team led by Siepmann, Eggimann, and Koenig to advance molecular simulation as a tool for high-fidelity property prediction and for providing molecular-level insights on phase and sorption equilibria. Specific applications relevant for biofuel production and detergent formulations will be addressed.
Intellectual Merit:
Model Development. The TraPPE (transferable potentials for phase equilibria) family of force fields will be extended at multiple levels of resolution. TraPPECG (coarse-grain) will include polymers, asphaltenes, and water; TraPPE?UA (united-atom) will add siloxane and vinyl chloride polymers; TraPPEEH (explicit-hydrogen) will address environmental pollutants and fermentation inhibitors. The range of systems and processes amenable to predictive simulations will be enlarged through the parameterization of TraPPE salt for inorganic ions and TraPPE zeo for porous zeolite frameworks. A web interface will be designed to increase the accessibility of the TraPPE force fields for other research groups. Algorithm Development. Novel Monte Carlo algorithms will be developed that can improve the sampling of phase transfers (e.g., in liquid-liquid equilibria and sorption isotherms from solution phases) and spatial distributions in microheterogeneous fluids (e.g,, surfactant systems). Applications. Molecular simulations using the TraPPE force fields will be employed as an engineering tool to predict thermophysical properties of a variety of complex systems, thereby adding to the available experimental database. The simulations will provide a wealth of microscopic-level insight into how molecular architecture and composition determine macroscopic phenomena. Specifically, simulations will be carried out to investigate (i) the solvent-based extraction of ethanol from fermentation broths, ii) the sorption isotherms of oxygenates and fermentation inhibitors from aqueous solution, (iii) the adsorption of surfactants at interfaces and to polyelectrolytes, (iv) the capacity limit of organics in micellar surfactants, and (v) the phase coexistence in mixed surfactant bilayers.
Broader Impacts:
Integration of Research and Education. Because the excitement of discovery is a significant motivating factor in student learning, computational exercises and topical results from molecular simulation research are routinely integrated by Siepmann and Eggimann in their classroom teaching (spanning from of a freshman seminar on the material world to graduate-level statistical mechanics). Hands-on science classroom for third graders have been taught by Siepmann and a full day of activities centered around computational chemistry is organized for UMN's Exploring Careers in Engineering and Physical Sciences Program. An active undergraduate research program is leveraged by Eggimann to promote general scientific literacy and research-as-teaching pedagogies. Development of Human Resources. This university industry partnership uniquely advances the education and training of the graduate students and postdoctoral associates by allowing for extensive interactions with industrial chemists and experience with real-world surfactant applications. Additionally, this project will foster the participation of undergraduate and high school students, with special efforts made to recruit these students from traditionally underrepresented groups. Impact on Science and Engineering Infrastructure. The microscopic-level understanding afforded by the proposed computational investigations will be highly beneficial for the design of improved separation processes for biofuels and surfactant systems. The computing infrastructure is advanced by the development of the TraPPE force fields, the associated cybertool, and the MCCCS (Monte Carlo for Complex Chemical Systems) molecular simulation package, which are freely distributed.
