Structure and stability of polymer/cyclodextrin inclusion complexes

CARB 109

Marcus A. Hunt, mahunt2@ncsu.edu, Department of Fiber and Polymer Science, North Carolina State University, Raleigh, NC 27695-8301, Alan E. Tonelli, alan_tonelli@ncsu.edu, Fiber and Polymer Science Program, North Carolina State University, Campus Box 8301, 2401 Research Drive, Raleigh, NC 27695-8301, and C. Maurice Balik, balik@ncsu.edu, Materials Science & Engineering, North Carolina State University, 911 Partners Way, Campus Box 7907, Raleigh, NC 27695.
Cyclomaltohexaose (α-cyclodextrin, α-CD) can form inclusion complexes (ICs) with polymer molecules in the columnar crystal in which α-CD molecules stack to form a molecular tube. Complementary water vapor sorption and wide-angle X-ray diffractomery (WAXD) were performed on α-CD ICs to determine their structure and stability. To discern the effect of guest molecule hydrophobicity on water adsorption isotherms, polyethylene glycol (PEG, MW = 600 g/mol) and hexatriacontane (HTC) were used. Sorption isotherms for PEG/α-CD IC are similar to those obtained for pure α-CD and PEG, suggesting the presence of dethreaded PEG in the sample. WAXD collected before and after water vapor sorption of PEG/α-CD IC indicated a partial conversion from columnar to cage crystal structure, the thermodynamically preferred structure for pure α-CD, due to dethreading of PEG. This behavior does not occur for HTC/α-CD IC. Elemental analysis and 1H NMR were employed to elucidate guest/α-CD stoichiometry.
 

General Contributed Papers: Synthesis
9:00 AM-11:00 AM, Thursday, 14 September 2006 Hilton San Francisco -- Yosemite C, Oral

Division of Carbohydrate Chemistry

The 232nd ACS National Meeting, San Francisco, CA, September 10-14, 2006