Sg. Urquhart et al., INNER-SHELL EXCITATION SPECTROSCOPY OF POLYMER AND MONOMER ISOMERS OFDIMETHYL PHTHALATE, JOURNAL OF PHYSICAL CHEMISTRY B, 101(13), 1997, pp. 2267-2276
The C 1s X-ray absorption spectra (XAS) of poly(diallyl phthalate), po
ly(diallyl isophthalate), and poly(ethylene terephthalate) (PET) have
been recorded using transmission detection. The phthalate segments of
these polymers are isomers with different patterns of substitution (or
tho, meta, para) of the methyl carboxylate groups on the phenyl ring.
The C 1s and 0 1s electron energy loss spectra (EELS) of the correspon
ding isomeric monomers, dimethyl phthalate, dimethyl isophthalate, and
dimethyl terephthalate, have also been recorded in the gas phase usin
g inelastic electron scattering under conditions dominated by electric
dipole transitions. Good agreement is found in overall shape and in t
he energies of the spectral features of the same isomer in monomeric (
EELS) versus polymeric (XAS) form. Ab initio calculations are used to
provide a detailed interpretation of the spectra, in particular the or
igin of the isomeric variations. The analytical potential for using in
ner shell excitation spectroscopy to identify isomeric character and t
o map spatial distributions of polymer isomeric substitution is assess
ed.