Friday May 5th – Presentations

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Development of an Acoustic Levitation Device for Probing Heterogeneous Chemistry in Planetary and Exoplanetary Atmospheres

Beni B. Dangi;*Jordan Dixon; Jared Golden

Department of Chemistry, Florida A & M University, Tallahassee, Florida

04:00 PM
to 04:20 PM
Physical Chemistry

We report development of experimental laboratory dedicated to the understanding of fundamental heterogeneous chemical processes in planetary and exoplanetary atmospheres. Even though number of exploration and detection of habitable worlds continue exponentially, there is scarcity of laboratories around the world that can generate fundamental data to understand the physics and chemistry of atmospheres of the new exotic worlds which are potential future habitats. Hence, now is the ideal time to establish laboratories that can shed light on physico-chemical processes, such as formation or destruction of cloud and haze, and catalytic conversion of gases on metallic and dust particle surfaces in such environments.

An ultrasonic levitator, which provides bulk-and-support free condition, has been acquired and tested for its performance. An ultrasonic levitator utilizes sound waves to suspend a solid particle or a liquid droplet without any support, except the gas medium. Furthermore, as opposed to some other trapping techniques, the sample can be held independent of its physical properties such as electric charge and refractive index. A process chamber has been custom built and acquired to enclose the levitator and control identity, proportion and pressure of gases for desired experiments. Incorporation of spectroscopic probes into the instrument is currently being designed which will allow to probe the physico-chemical changes in situ.

Self-organization of layered inorganic membranes in microfluidic devices

Qingpu Wang, Megan R. Bentley, and Oliver Steinbock

Department of Chemistry and Biochemistry, Florida State University,
Tallahassee, Florida 32306-4390

04:20 PM
to 04:40 PM
Physical Chemistry

Inorganic precipitate membranes play an important role in chemobrionics and origin of life research. They can involve a range of catalytic materials, affect crystal habits, and show complex permeabilities. We produce such membranes in a microfluidic device at the reactive interface between laminar streams of hydroxide and Co(II) solutions. The resulting linear membranes show striking color bands that over time expand in the direction of the Co(II) solution. The cumulative layer thicknesses (studied up to a total value of 600 µm) obey square root laws indicating diffusion control. The effective diffusion coefficients are proportional to the hydroxide concentration but the membrane growth slows down with increasing concentrations of Co(II). Based on spatially resolved Raman spectra and other techniques, we present chemical assignments of the involved materials. Electron microscopy reveals that the important constituent b-Co(OH)2 crystallizes as thin hexagonal microplatelets. Under drying, the membrane curls into spirals revealing mechanical differences between the layers. Our results also provide chemical insights into the pattern formation of chemical gardens.

Ion Solvation of Transition Metals in Differential Mobility Spectrometry

Ayodeji, Ifeoluwa; Vazquez, Timothy; Bailey, Ronelle; Mancuso, Christina; Evans-Nguyen, Theresa.

University of South Florida; Department of Chemisty; Tampa, FL

04:40 PM
to 05:15 PM
Physical Chemistry

Differential mobility spectrometry is a rapid means of chemical separation that is leveraged in place of chromatography prior to mass spectrometry.  We have incorporated it as a filtration scheme for the separation of transition metals and recently small organic molecules.  One mechanism for separation is speculated to involve the ions’ microsolvation by residual water vapor.  Experimentally, such phenomena are ultimately tied to the ionization method.  In previous work, we relied on a nanoelectrospray ionization method but more recently have incorporated other solvent-less methods such as atmospheric chemical ionization.  In this manner, we hope to tease out the role of the water clusters in the separation observed by DMS.  We shall present our preliminary work to understand this phenomenon.