Grant: Research Tools and Instruments

The stopped flow spectrometer is used to measure the speed of chemical reactions that occur in milliseconds. Measurements of the kinetics for chemical reactions that occur in milliseconds are too fast to be studied by mixing solutions by hand. In a stopped-flow experiment two different solutions contained in two syringes are mixed in the mixing chamber by the application of pressure to the syringes. The chemical reactions are followed by either measuring the absorption or the emission (fluorescence) for the reagents that disappear or for the products that appear. The requested system includes the ability to analyze data where multiple reactions occur simultaneously or in sequence. The stopped-flow spectrometer is the central equipment for our studies in supramolecular dynamics. Supramolecular chemistry occupies the space between individual molecules and macroscopic systems in terms of complexity and functionality. Supramolecular systems are always reversible with the continuous interconversion between molecular building blocks and supermolecules. The various species in a system co-exist and compete with one another. The characterization of any supramolecular system requires studies on the interconversion between species, and this information can only be obtained from kinetic studies, where we observe the system evolving toward its equilibrium state. The objective of my research program is to understand how increases in complexity affect the outcomes of each system in order to create a conceptual framework on how the system's complexity can be purposely exploited to achieve the types of emergent properties seen in living systems. This conceptual framework can then be applied to the rational design of functional materials. In one research project we will determine the minimum requirements to build a system where the components can be kept away from equilibrium, while energy in the form of light is provided to the system. These studies rely on the host-guest chemistry of a versatile class of macrocyclic hosts (cucurbit[n]urils). The second area of research focusses on the understanding on how hydrogels form and how the structure of these materials affects the mobility within these materials. The first project advances the fundamental understanding on the function of supramolecular systems. This understanding is applicable to the field of systems chemistry, where the focus is to embrace complexity to explain the emergence of new properties that cannot be predicted from the properties derived from the studies of interactions between individual molecules. The second project will have impact on the design of any gel where the function requires the movement of molecules within the material and between the material and the external environment. The outcome from the second project will lead to the development of better functional materials, such as the development of tailored drug delivery systems.