Hot filament chemical vapor deposition of poly(glycidyl methacrylate) thin films using tert-butyl peroxide as an initiator

We have demonstrated the successful deposition of poly(glycidyl methacrylate) (PGMA) thin films using hot filament chemical vapor deposition (HFCVD) with tert-butyl peroxide as the initiator. The introduction of the initiator allows for film deposition at low filament temperatures (<200 degreesC) and greatly improves the film deposition rates. The retention of the pendant epoxide chemical functionality and the linear polymeric structure in the deposited films were confirmed by infrared spectroscopy and X-ray photoelectron spectroscopy. The number-average molecular weight of the PGMA films can be systematically varied from 16 000 to 33 000 by adjusting the filament temperature and flow ratio of the initiator to the precursor. The apparent activation energies observed from PGMA deposition kinetics (100.9 +/- 9.6 kJ/mol) and from molecular weight measurements (-54.8 +/- 2.0 kJ/mol) are close to the calculated overall activation energies for the polymerization rate (104.4 kJ/mol) and number-average molecular weight (-59.2 kJ/mol), which supports the hypothesis of the free radical polymerization mechanism in the HFCVD PGMA deposition.