College Park, Maryland      June 6 - 10 , 2004

MP12: Solvent Induced Stiffness in Poly(ethylene oxide)

M.L. Alessi (University of Maryland, Department of Chemical Engineering), D.L. Ho (NIST Center for Neutron Research), S.C. Greer (University of Maryland, Department of Chemical Engineering; Department of Chemistry and Biochemistry)

Poly(ethylene oxide) (PEO) is a simple polymer with repeating units [- C - C - O -] soluble in organic and aqueous solvents. In all solvents in which PEO has previously been studied, the PEO molecule forms a coil in solution. Small-angle neutron scattering of PEO in deuterated isobutyric acid shows a dramatic stiffening of the polymer chains, resembling a rod. Infrared spectroscopy and polarimetry measurements indicate that the rods are helical. PEO has been seen to form a helix in the solid phase and a local helical structure in aqueous solvents. A global helical conformation, however, has not been seen before in solution. The formation of nanoscale PEO rods may have applications in nanotechnology.

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