CHEM Seminar - Uncovering the Rules of Liquid Mixtures: The Obvious and The Not-So-Obvious

Speaker: Professor Bilin ZHUANG

Institution: Division of Science (Chemistry), Yale-NUS College, Singapore

Hosted By: Professor Haibin SU

Abstract

Liquid mixtures are ubiquitous. An obvious rule for liquid mixtures is the empirical “like-dissolves-like” rule, which we are familiar with. However, how “like” must the liquids be to mix well? This question does not yet have a good quantitative answer. In the first part of the talk, I will address this question by developing a statistical field theory for liquid mixtures. The theory avoids the use of ad hoc mixing rules and instead considers a statistical description of mixture interactions. Without the use of any adjustable parameters, the theory accurately predicts the miscibility of a variety of liquids, and thus provides quantification for the well-known “like-dissolves-like” rule. In the second part of the talk, I will venture into a not-so-obvious liquid mixture – the pure water. Wait, is pure water a mixture? In fact, the unique anomalous properties of water (such as the density maximum at 4oC) point to the hypothesis that water is a mixture of two interconvertible organizations of hydrogen-bonding structures. However, the exact geometries of these structures have not been elucidated. Here, we decipher the “mixture” that forms water through molecular dynamics simulations. In addition, by considering the temperature dependence of the hydrogen-bonding structures, we explain a water’s transition at around 60oC recently discovered by the experimentalists.

About the speaker

Dr. Zhuang Bilin is currently an assistant professor of chemistry at Yale-NUS College in Singapore. Her research focuses on theoretically understanding the complex structural and dynamic properties of soft matter systems, through both analytical theories and numerical simulations. Bilin received her B.A. degree in 2009 from Wellesley College, a women’s liberal arts college in the United States, with double majors in physics and chemistry. Thereafter, she moved to the California Institute of Technology and received a Ph.D. degree in Chemistry in 2016. Her graduate research involved developing statistical field theories for liquid mixtures under both equilibrium and non-equilibrium conditions, which provided solutions to several long-standing challenges in the field of physical chemistry theory. Bilin is a recipient of the American Physical Society LeRoy Apker Award, A*STAR Career Development Award, and the AME Young Individual Research Award.