Ions exist at delicate equilibrium between intra and extracellular environments, and comprise important mediators of cellular activity. This is closely tied to their chemical properties and interactions with different materials. This study probes ion interactions with ester carbonyls at the interface of membrane environments with simple model systems. Carbonyls are ubiquitous in biological systems and represent important probes of molecular dynamics in a variety of applications even beyond biomolecules from synthesis to materials sciences. Because these systems are especially sensitive to changes in their solvent environments, ions can heavily promote or disrupt the integrity of otherwise ordered arrangements.<br/>This presentation examines our recent findings on ion interactions in these systems. First, we examined the effects of monovalent and divalent ions on spectral line-shape changes in the carbonyl stretches of ethyl acetate. We have found the number of ion bound species demonstrates a direct dependence on monovalent ion concentration, but appears to have an inverse relationship for divalent ion concentration, due to complete displacement of hydrogen bonded populations and stronger overall cation binding. These relationships speak to the effects of the same ions on more complex reverse micelle systems. We have found surprisingly, that calcium ions both readily disrupt interfacial head groups, while promoting ordering among tail groups.<br/>From commercially applicable surfactants and colloids to interactions at the interface of cellular systems, fundamental characteristics of multi-phase systems are just beginning to be understood. This study will discuss how precise understandings of small-scale models can facilitate interpretations of more complex phenomena.<br/>

Characterization of monovalent and divalent ion interactions in interfacial esters

255th National Meeting (2018)

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