Strong fragmentation processes driven by low energy electron attachment to various small perfluoroether molecules.

Area of Science:

• Physical Chemistry
• Materials Science
• Surface Science

Background:

• Perfluoroethers (PFEs) are used in various applications.
• Understanding their interaction with electrons is crucial for material stability and performance.
• Degradation mechanisms in PFEs are not fully understood.

Purpose of the Study:

• Investigate negative ion formation in diglyme, triglyme, and crownether PFEs.
• Determine the role of low-energy electron attachment in PFE decomposition.
• Correlate electron-induced fragmentation with observed PFE properties in applications.

Main Methods:

• Electron attachment experiments in the energy range of ~0 to 15 eV.
• Analysis of negative ion fragments using Mass-analyzed Ion Kinetic Energy (MIKE) scans.
• Study of dissociative electron attachment (DEA) pathways.

Main Results:

• Intense low-energy resonances (<3 eV) observed in all three PFEs, leading to fragment ions via DEA.
• Sequential decompositions on the microsecond timescale were detected for some fragments.
• Perfluorocrownether showed a parent anion signal, unlike the other two PFEs.
• Weaker resonances at higher energies (~10-17 eV) decomposed into lighter ions.

Conclusions:

• PFEs exhibit significant sensitivity to low-energy electrons, driving fragmentation.
• This electron sensitivity likely explains PFE behavior in applications, such as UV-induced surface bonding and hard disk drive degradation.
• The findings provide insights into the fundamental interactions governing PFE stability and performance.