Journal of Nanomedicine & Nanotechnology

Pore size distributions measurement of mesoporous TiO2 by nuclear magnetic resonance cryoporometry

3^rd International Conference on Nanotek & Expo

December 02-04, 2013 Hampton Inn Tropicana, Las Vegas, NV, USA

Seung-Yeop Kwak and Su-Yeol Ryu

Accepted Abstracts: J Nanomed Nanotechnol

Abstract:

This work describes the pore size measurement by nuclear magnetic resonance (NMR) cryoporometry. Cryoporometry is a superior porosimetry measurement to analyze the pore-size and pore-size distributions (PSDs) with nanoscale pores (1- 100 nm). NMR cryoporometry, which is non-destructive measurement, is based on the theory of the melting point depression (MPD) of a probe-molecule confined within a pore, which is dependent on the pore diameter. Hydrophilic and/or hydrophobic pore can be measured using a probe-molecule which is sensitive to the hydrophilic and/or hydrophobic circumstance. In order to measure PSDs of mesoporous TiO 2 spheres with various pore sizes, NMR cryoporometry measurements were conducted using hydrophobic probe-molecule. MPD was determined by analyzing the variation of the NMR signal intensity with temperature. From the resulting spin-echo intensity versus temperature curves, it was found that maximum MPD of hydrophobic liquid confined within pores of the mesoporous TiO 2 decreases with increasing calcination temperature, i.e., the pore size increases with increasing calcination temperature. We also confirmed with Barrett-Joyner-Halenda (BJH) analysis that the pore size of mesoporous TiO 2 . This trend is in agreement with our NMR cryoporometry results. Overall, these findings indicate that NMR cryoporometry measurement is very effective methods for determining PSDs of mesoporous materials

Biography :

Seung-Yeop Kwak obtained a B.S. degree from the Department of Textile Engineering at the Seoul National University, Seoul, Korea in 1987. He received his M.S. (1989) and Ph.D. (1992) both under the supervision of Professor N. Nakajima in the Department of Polymer Engineering from the University of Akron, Akron, Ohio, USA. He completed his thesis work on polymer nanostructure. His current research interests are membranes for advanced water treatment and for separator of secondary battery. Other interests are eco-friendly plasticizer for replacement of endocrine-disrupting plasticizer. In addition, he also interested in analyses of nanostructure and molecular mobility, i.e., solid-state NMR