XPS studies of chain conformation in PEG, PTrMO, and PTMG linear polyethers

X-ray photoelectron spectra are reported for ordered and disordered chain c onformations of pc,ly(ethylene glycol) and poly(tetramethylene glycol). Bot h polymers show a conformational dependent intensity change at the top of t he (C 2s + O 2s) band of the valence level spectrum, which is interpreted a s due to changes in through-space interactions in the corresponding molecul ar orbitals on going from ordered to disordered chains. We support these co nclusions with self-consistent field calculations on model conformations of a poly(ethylene glycol) oligomer. The spectral features at the top of the (C 2s + O 2s) band in the simulated spectra show a strong dependence on rot ation about the C-O links of the oligomer chain. The core level spectra of poly(ethylene glycol) and poly(tetramethylene glycol) show no conformationa l dependence. Angle dependent valence band studies show the presence of a d isordered layer at the uppermost surface of a crystalline sample of poly(et hylene glycol). Time dependent valence band studies demonstrate X-ray induc ed conformational disordering due to chain scission and cross-linking. For poly(trimethylene oxide) core and valence level spectra of only the disorde red polymer are reported.