The elastic modulus of isolated polytetrafluoroethylene filaments

We report vibrational Raman spectra of small extended perfluoro-n-alkanes (CnF2n+2 with n = 6, 8–10, 12–14) isolated in supersonic jet expansions and use wavenumbers of longitudinal acoustic vibrations to extrapolate the elastic modulus of cold, isolated polytetrafluoroethylene filaments. The derived value E = 209(10) GPa defines an upper limit for the elastic modulus of the perfectly crystalline, noninteracting polymer at low temperatures and serves as a benchmark for quantum chemical predictions.