The Blanchard group research is focused on three problems of interest to the analytical chemistry and materials science communities. These are (1) Design and characterization of molecular monolayer and multilayer assemblies, (2) Understanding energy exchange processes between dissimilar molecules, and (3) Achieving a molecular understanding of crystallization from saturated and super-saturated solutions. We use picosecond nonlinear laser spectroscopies in conjunction with more traditional methods to address these problems.

Monolayer and multilayer assemblies. Organic-modified interfaces have found wide use in chemistry, physics and materials science. The popularity of molecular interfaces stems from the fact that a very small amount of material can alter the properties of the system dramatically. We have investigated alkanethiol self-assembling monolayers, with an emphasis on their formation and the extent of structural freedom that exists within the layer.

We are developing an effort in metal-phosphonate multilayer chemistry, where molecular assemblies can be made that are many layers thick with each layer possessing a unique chemical identity. There are two primary questions that we focus on in this work: (1) Can we control the speed of energy migration and the ultimate location of energy placed in these systems? and (2) How can we determine the density and types of defects within the multilayers?

Understanding vibrational energy exchange between dissimilar molecules. We are also interested in understanding how dissimilar molecules interact and what role molecular scale organization plays in determining the bulk properties of a given system. We have focused on vibrational energy transfer and have developed a unique means to measure the vibrational population relaxation dynamics of dilute fluorophores in solution. Our data reveal abundant evidence for local organization even in nonpolar liquids, and the central focus of this project is now on understanding more generally how to predict this local organization based on the chemical structures of the constituents.

How do crystals form? Although this may be a simple question, there is not a simple answer. While crystallization from solution is used widely in industry to purify products, controlling or even detecting the onset of crystallization has remained an elusive goal. In a joint effort with Professor Berglund’s group, we use a lock-and-key approach to answering this question. We probe crystallizing systems using fluorescent molecules that contain a pendant moiety the same as that of the crystallizing species. This approach has provided valuable insight into the apparent absence of long-lived pre-crystalline aggregates in solution, suggesting the dominance of kinetic factors in mediating crystallization.