Neutron vibrational spectroscopy gives new insights into the structure of poly(p-phenylene terephthalamide).
The vibrational spectra of benzanilide and poly(p-phenylene terephthalamide) have been measured using inelastic neutron scattering. These compounds have similar hydrogen-bond networks, which, for poly(p-phenylene terephthalamide), lead to two-dimensional hydrogen-bonded sheets in the crystal. Experimental spectra are compared with solid-state, quantum chemical calculations based on density functional theory (DFT). Such "parameter-free" calculations allow the structure-dynamics relation in this type of compound to be quantified, which is demonstrated here for benzanilide. In the case of poly(p-phenylene terephthalamide), vibrational spectroscopy and DFT calculations help resolve long-standing questions about the packing of hydrogen-bonded sheets in the solid state.
Plazanet
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Institut Laue Langevin, BP156, 38042 Grenoble Cedex 9, France.
Fontaine-Vive
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Gardner
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Forsyth
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Ivanov
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Ramirez-Cuesta
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Johnson
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