Deposition and Characterisation of Plasma Polymerised Allyl Methacrylate Based Coatings

Abstract

Allyl methacrylate (AMA) was deposited on aluminium using atmospheric dielectric barrier discharge plasma. AMA posseses two CC bonds which have very different reactivities and the efficiency of the plasma on polymerising the two different kinds of double bonds was evaluated. The Fourier transform infrared spectra and the nuclear magnetic resonance spectra of the plasma coatings were compared with those of conventionally synthesised poly(AMA). The influence of the monomer feed on the ester, the vinyl and the allyl functionalities of the coatings were investigated. Plasma coatings showed lower concentration of non‐reacted allyl groups than conventional poly(AMA) suggesting a more cross‐linked network. Pull‐off adhesion tests were performed after the deposition of the a topcoat to evaluate the potential use of the AMA based coatings as adhesion promoter.

Deposition Kinetics and Thermal Properties of Atmospheric Plasma Deposited Methacrylate-Like Films

“…However, due to the lower reactivity of the allylic C5 5C group compared to the methacrylic group, a fully cross-linked poly(AMA) benchmark system cannot be obtained. [26,42] The propyl isobutyrate precursor (see Figure 1, (PiB)) is the fully saturated analog of AMA, and therefore cannot be polymerized through conventional polymerization reactions. Methyl methacrylate (see Figure 1, (MMA)) has one C5 5C double bond and gives rise to a linear polymer, PMMA, through conventional free radical polymerization.…”

“…Allyl methacrylate has a methacrylic and allylic C5 5C double bond and has been used as precursor in an atmospheric DBD reactor for the production of pdAMA films. [26][27][28][29] Based on FTIR, XPS, and solid state 13 C NMR, it was concluded that highly cross-linked pdAMA films were obtained. In comparison to AMA, the plasma deposition rate of the analogous fully saturated PiB was found to be four times lower at a constant Yasuda factor (Y f , in kJ g À1 ), i.e., input plasma power (in W) per precursor mass feed rate (in mg s À1 ).…”

Challenges in the characterization of plasma polymers using XPS

“…[17,142]. These vibrations even enable discrimination, for instance, between the allyl and the vinyl groups [17].…”

“…Because of their huge utilization in industry, oxygenated hydrocarbons such as acrylates have been widely synthesized by plasma, both at low and high pressure. References [17,28,[99][100][101][102][103][104][105][106][107][108] report XPS characterizations of some acrylate coatings (from poly(acrylic acid) to poly(methyl methacrylate)) deposited by plasma. In most of these papers, no differentiation between carboxylic acid and ester groups is envisaged and second neighbors are not necessarily considered.…”

“… Helpful to determine the evolution of C=C in pp as a function of plasma deposition conditions, with relatively well resolved peaks [17,118].…”