Valeria Molinero

Valeria Molinero

PHYSICAL & MATERIALS CHEMISTRY

Professor
Director, Henry Eyring Center for Theoretical Chemistry

Ph.D. University of Buenos Aires, 1999
Postdoctoral Researcher, California Institute of Technology, 2000-2003
Associate Researcher, Arizona State University, 2005-2006
Associate Scientist, California Institute of Technology, 2003-2006

 

Phone: (801) 585-9618

Office: 4623 Thatcher Building

Email: valeria.molinero@utah.edu

Research Group

Activities & Awards

  • Extraordinary Faculty Achievement Award, 2016

  • Camille Dreyfus Teacher-Scholar Award, 2012

  • College of Science Myriad Faculty Award for Research Excellence, 2011
  • Beckman Young Investigator Award, 2009
  • Helmholtz Award, International Association for the Properties of Water and Steam, 2005

Research Interests

We use computer simulations, statistical mechanics and develop novel models to investigate the interplay between microscopic structure, dynamics and phase transformations in disordered materials.

Structure and anomalies of liquid water and its solutions. Liquid water presents a series of thermodynamic, structural and dynamical anomalies that become the most pronounced in the supercooled region of the phase diagram. We investigate the origin of the anomalies, the development of long-range structural correlations in supercooled liquid water and the effect of the increase in the tetrahedrality of liquid water on the structure and phase segregation of aqueous solutions of salts.

decoupled diffusion of ions

Nanophase segregation of aqueous solutions of LiCl as they are vitrified through hyperquenching.

Mechanisms of ice crystallization in bulk and confined water. One of water’s unsolved puzzles is what determines the lowest temperature at which liquid water and aqueous solutions can be cooled before freezing to ice. We use molecular simulations to elucidate the mechanism of water freezing and its relation to the thermodynamics and structure of supercooled water.

decoupled diffusion of ions

Development of cubic (red) and hexagonal (green) ice in the crystallization of liquid water at 180 K.

Nanoconfinement affects the phase behavior of water.Our work demonstrates that a bilayer of water can form a variety of novel structures based on pentagons, including a dodecagonal quasicrystal.

Nucleation and Growth of Clathrate Hydrates. Clathrate hydrates are crystalline inclusion compounds of water and small molecules that such as carbon dioxide or methane. The concentration of the gas molecules in the hydrates is about 100 times larger than in solution. A main question is how do the clathrates form if the water and gas do not mix. We use molecular dynamics simulations with efficient coarse-grained models to investigate the stability and mechanisms of nucleation and growth of clathrate hydrates of guests with a wide range of sizes and hydrophilicity. The main questions we address are what are the structures of the clathrate nuclei and what are the mechanisms of their formation from two-phase fluid systems and from ice.

decoupled diffusion of ions

Our simulations unravel a multistep mechanism of nucleation of clathrate hydrates that involves amorohous intermediates. Our work demonstrates that amorphous nuclei can grow crystalline clathrates.

The state of water in nanoporous and nanostructured materials. Water is ubiquitous in biological and synthetic materials, where is often confined by a matrix. A goal of our research is to understand how the structure of the material and intermolecular interactions determine the distribution of water and the stability and metastability of water’s liquid state. We investigate disordered systems with soft confinement, where the matrix is a rubbery polymer or a viscous supercooled liquid, and with hard confinement, such as mesoporous silica.

Hydrated Nafion in a multi-scale heterogenous material
nanostructure of hydrated Nafion
Coarse Grained Modeling Atomistic & Coarse Grained Modeling Atomistic Simulations

Hydrated Nafion in a multi-scale heterogenous material nanostructure of hydrated Nafion

decoupled diffusion of ions

Development of coarse-grained models.Most of our work involves the study of phenomena that occur over times that makes them inaccessible to state of the art atomistic simulations. To address this issue we have developed very efficient coarse-grained molecular models of water, electrolytes, solvated DNA, and methane. For example, water can be modeled as an element of the group IV with tetrahedrality intermediate between carbon and silicon. The goal of developing coarse-grained models is two-fold: First, to simulate much longer time scales and larger systems at a small fraction of the computing cost, and thus to build the tools needed to tackle new, and so far untreatable, problems. The second, and most fundamental, goal of developing coarse-grained models is to understand what level of details is needed to reproduce (some? which ones?) physical properties of a substance. In this sense, the coarse-grained model, as all models and theories, allows us to extract a fundamental understanding of the molecular and macroscopic behavior of matter and put our hypothesis (and prejudices!) to test.

Selected Publications

 

Patents

U.S. patent US60578034, "Fluorinated imidazoles as proton carriers for water-free proton exchange membranes for fuel cells". Inventors: W.A. Goddard III, W. Deng, and V. Molinero.