Structure and Morphology of Poly(isobenzofuran) Films Grown by Hot-Filament Chemical Vapor Deposition

Abstract

We describe hot-filament chemical vapor deposition of poly(isobenzofuran) (PIBF) films and characterize their chemical structure and surface morphology. The precursor monomer, 1,2,3,4-tetrahydro-1,4epoxynaphthalene, is pyrolyzed by flowing it over an array of hot filaments held at three different temperatures (680, 738, and 800 °C). The produced intermediate, isobenzofuran (IBF), is deposited onto a silicon substrate as thin films of PIBF. Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy revealed that the films prepared at 800 °C possess a chemical structure and a composition different from those prepared at lower filament temperatures (680 and 738 °C). Increasing filament temperature also leads to the formation of defect domains in the polymer films. By atomic force microscopy, we observe a decrease in surface roughness and in the average size of polymer grains in PIBF domains as the filament temperature is increased. Defect domains exhibit a rougher surface as well as larger size polymer grains than those in PIBF domains. Spectroscopic and microscopic results suggest that growth of the polymer in the defect domains proceeds by a mechanism different from that in the PIBF domains.

Chemical Vapor Deposition of Conformal, Functional, and Responsive Polymer Films

“…In the absence of a plasma, the large energetic barrier to creating charged species in the gas phase guarantees that heterogeneous processes will be the dominant pathways for reactions of ions. Explicit reports of ionic chain polymerization in CVD are limited but include the cationic polymerization of isobenzofuran 29–31…”

Directed Growth of Poly(isobenzofuran) Films by Chemical Vapor Deposition on Patterned Self-Assembled Monolayers as Templates

“…Methods for the solution-based polymerization of IBF often result in many undesirable byproducts and low molecular weight polymers due to the very poor stability of IBF and its derivatives. Recently, we demonstrated that poly(isobenzofuran) (PIBF) can be prepared as high-quality polymer thin films by thermal CVD and hot-filament CVD (HFCVD) processes , and discovered that the growth of PIBF is surface-dependent. Specifically, the growth rate of PIBF films grown by the CVD process can be greatly affected by surface functional groups with different acidities present on the target substrates.…”