PERFLUORO-POLY(ETHERS) WITH HYDROXYL END-GROUPS - ANALYSIS BY TOF-SIMS

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.