Basic Information

Abstract Number: 1590 - 3
Author Name: Joel M Harris - University of Utah
Session Title: A 60 Year Celebration of the Coblentz Society
Event Type: Symposia
Event Title: Probing Liquid/Solid Interface Chemistry Within Porous Particles by Confocal Raman Microscopy

Presider Name:Bruce ChaseCo-Author:Jay P Kitt
Affiliation:University of DelawareAffiliation:University of Utah

Date: Wednesday, March 11, 2015
Start Time: 09:10 AM (Slot #3)
Location: 244

Abstract Content

Practical applications of liquid/solid interface chemistry including catalysis, selective adsorption of molecules, chromatographic separations, and environmental remediation, generally employ porous support materials for immobilizing ligands or reactive sites. The high surface area of porous particulate materials provides large capacities for adsorption, reaction, or catalysis. While flat surfaces are often used as models for these materials for spectroscopic investigation, the surface chemistry of porous materials cannot be totally understood by study of flat surfaces. The challenge for spectroscopic investigation of porous materials is that most (>99%) of their surface area resides within the porous structure; thus relevant methods to investigate these materials must be capable of interrogating chemistry inside the porous structure. To address this measurement challenge, we employ confocal Raman microscopy to determine the chemical composition, interface structure, and surface interactions of molecules within individual porous particles. The pore structure of these particles is much smaller than the wavelength of excitation or scattered radiation and allows diffraction-limited imaging within the particle interior. The high specific surface area of these particles (>100 m[sup]2[/sup]/g) allows sub-monolayer coverages of molecules to be detected in Raman scattering without any enhancement. Confocal Raman microscopy is capable of unraveling retention mechanisms involved in chromatographic separations. It is also being developed for single-particle, solid-phase extraction to enable rapid, ultra-trace-level Raman scattering detection in sub-fL volumes. The methodology is being applied to measurements of octanol-water partitioning within silica particles whose pores filled with octanol. Finally, the method can be used to determine solute interactions with hybrid-lipid bilayers supported on n-alkyl chain ligands within individual, porous-silica particles.

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