Structure and Thermal Properties of Thin Film Poly(α‐methylstyrene) Deposited via Plasma‐Enhanced Chemical Vapor Deposition

Abstract

Plasma-enhanced (PE) CVD from a-methylstyrene is a dry method for synthesizing directly patternable sacrificial materials for generating pores or air dielectric layers. Films deposited at low power excitation (40 W) decompose between 65 C and 75 C, leave minimal residue following a 400 C anneal for 2 h, and have spectroscopic signatures of linear poly(a-methylstyrene) (PaMS) as determined by nuclear magnetic resonance (NMR) spectroscopy and Fourier transform infrared (FTIR) spectroscopy. Increased plasma excitation power leads to cross-linking and increased residue after annealing. All films also contain hydroxyl and carbonyl groups after exposure to air. Significant C±O±C inclusion occurs under continuous plasma excitation but not under pulsed-plasma conditions.

Ageing and thermal degradation of plasma polymerised thin films derived from Lavandula angustifolia essential oil

“…For the 10 W sample, thermal degradation begins to occur at approximately 60 C. The 25 W sample also begins degradation at the same temperature, however has two regimes with the second commencing at approximately 170 C. The same phenomena has been observed for plasma polymerised a-methylstyrene and was credited to the desorption of low molecular weight species before the onset of bulk decomposition [28]. Onset for thermal degradation for the 50 and 75 W samples occurs at approximately 130 and 170 C respectively.…”

“…The uptake of oxygen into the polymer structure is not as strong in comparison to other plasma polymers [28] where the inclusion of additional hydroxyl (C-O, 1205-1125 cm À1 ) and carbonyl (C]O, w1700 cm À1 ) groups have been reported for plasma polymerised a-methylstyrene for similar ageing periods. Additionally, from the ellipsometry measurements the bulk of the ageing in these films occurs within the first 5 days after fabrication.…”

Kinetic equations for thermal degradation of polymers

“…(38), (39) and (40) that one should set a = 0 and b = 2 in Eq. (35) in order to reproduce the experimental data plotted in Figure 7.…”

Initiated CVD of Poly(methyl methacrylate) Thin Films

“…[25] The electric discharge in PECVD can lead to loss of functionalities, but retention of pendant functional groups can be improved via pulsation of the plasma. [26] iCVD can be positioned as a complementary method to PECVD in depositing polymer thin films. In contrast to PECVD, there is no UV irradiation or ion bombardment in the iCVD process, so the resulting films have lower densities of dangling bonds and crosslinks than films grown using plasma excitation.…”