Ph. Kasai et Am. Spool, PERFLUORO-POLY(ETHERS) WITH HYDROXYL END-GROUPS - ANALYSIS BY TOF-SIMS, JOURNAL OF PHYSICAL CHEMISTRY B, 102(38), 1998, pp. 7331-7337
TOF-SIMS spectra of perfluora-poly(ethers) (PFPE) with hydroxyl end gr
oup(s), Fomblin Z-DOL, Krytox-OH, and Demnum-SA, were analyzed. Previo
usly we have observed that while the positive-ion TOF-SIMS spectra of
nonfunctionalized PFPEs are complex and compressed toward the low mass
end, the negative-ion spectra show intense simple patterns persisting
into a high mass region surpassing the mean molecular weight of the p
olymer. The rich negative-ion spectra of nonfunctionalized PFPEs are a
scribed to anions generated by one-event dissociative capture of low-e
nergy secondary electrons by ether oxygens of the polymer backbone: R-
O-R' + e(-) --> R-O- + R-.'. In stark contrast to nonfunctionalized PF
PEs, PFPEs with hydroxyl end group(s) showed, in the positive-ion spec
tra, a fragmentation pattern persisting into the high mass region and
a pattern clearly associated with the parent molecule (molecular weigh
t) distribution. In the negative-ion spectra, the pattern due to anion
s R-O- encompassing the hydroxyl sector was totally absent. The observ
ed anomalies can be accounted for if one postulates that PFPEs with hy
droxyl end group(s) have a strong propensity to ionize at the hydroxyl
sector. A possible relevance of such a propensity to the bonding mech
anism of Z-DOL (Fomblin Z with hydroxyl end groups) to the carbon over
coat of magnetic recording disks is conjectured.