Phase-Behavior and Complexation in Polyelectrolyte -Particle Mixtures

University Of Texas At Austin, Austin TX

Investigators

Abstract

TECHNICAL SUMMARY This award supports theoretical and computational research and education to advance understanding of particle- and protein-polyelectrolyte mixtures. This research is motivated by three unresolved fundamental questions: (i) What is the impact of the interplay between electrostatic and polymer solution fluctuation effects in determining interparticle interactions and complexation characteristics in polyelectrolyte solutions ? (ii) What is the influence of multibody interaction effects upon the structure, complexation characteristics and thermodynamic behavior of polyelectrolyte-particle mixtures ? (iii) What is the impact of physicochemical features such as pH effects, charge heterogeneities on particles, enthalpic polymer-particle interactions and solvent quality upon the structure, thermodynamic behavior and complexation characteristics of polyelectrolyte -particle mixtures? To address these questions, the PI aims to develop a framework that combines field theory- and particle- based approaches to study the interplay of electrostatic and polymer density fluctuations, multibody and curvature effects and their influence upon the fundamental physics of charged polymers interacting with particles. The PI will use the framework to study the influence of various physicochemical parameters upon the polyelectrolyte adsorption behavior, chain conformational characteristics, interparticle interactions and the phase behavior of polyelectrolyte-particle mixtures. The simulation approaches developed in the course of the research will be used to develop simulation modules that will illustrate the role of fluctuation phenomena and multibody effects. These modules will be used in the graduate and undergraduate courses, and will also be integrated into different outreach activities and web-based module repositories to be used in classrooms throughout the country. This project will involve minority undergraduate student researchers recruited through their Texas Research Experience application program. NONTECHNICAL SUMMARY This award supports theoretical and computational research and education with aim of advancing our understanding of mixtures containing long chain-like molecules with repeating molecular subunits, polymers, and particles or protein molecules. The PI will focus on a particular class of polymers, polyelectrolytes, that acquire an electric charge in solution. Because of the electric charges, there are additional interactions among the long molecular chains and also between the chains and the particles or proteins also present in the solution. The PI will advance conceptual understanding of these mixtures and develop new ways to use computers to simulate them. A better understanding of these mixtures has potential impact on understanding important biological processes, the food industry, particularly on the texture, stability, and taste of engineered food, and methods for synthesizing materials to achieve desired properties. The simulation approaches developed in the course of the research will be used to develop simulation modules that will be used in graduate and undergraduate courses. They will also be integrated into different outreach activities and web-based module repositories to be used in classrooms throughout the country. This project will involve minority undergraduate student researchers recruited through their Texas Research Experience application program.