Plasma Polymerization of APTES to Elaborate Nitrogen Containing Organosilicon Thin Films: Influence of Process Parameters and Discussion About the Growing Mechanisms

Abstract

Plasma polymerization of 3‐aminopropyl‐triethoxysilane (APTES) in microwave late afterglow was studied. First, sol‐gel polymerized APTES was prepared and characterized by ATR–FTIR and XPS. The results obtained were used as a model to define the nature of nitrogen containing groups in the plasma polymer layers. It is shown that the variation of process gas mixture gives the possibility to tailor the chemical composition of the coatings. We show that nitrogen can be present in the thin films as amines, amides, imines or oximes. The analysis of the gas phase composition by OES during the deposition process was realized and based on the correlations established between OES results and thin film compositions, some assumptions on the chemical mechanisms involved in the gas phase are discussed. magnified image

Adhesion Improvement between Epoxy and Stainless Steel Using a Silane Coupling Agent in an Atmospheric Plasma Process

“…Note that the N/Si ratio for all coatings is approximately 1.0 as expected for the APS precursor. The O/Si and O/N ratios (Table 5) confirm [55,60] 23 AE 2 2 2AE 2 2 3 AE 2 C1 285.0 AE 0.2 C-C/C-R (H) [55,60] 31 AE 2 3 7AE 2 2 5 AE 2 C2 286.0 AE 0.2 C-N [55,60] 13 AE 2 2 1AE 2…”

“…In fact, although the lowest possible power was chosen for the plasma coating deposition to preserve the precursor chemical structure injected into [53,55] -1 720 1 720 C5 5O stretch (aldehyde, ketones, carboxylic acid) [55] -1 680 1 680 C5 5O stretch (amides) [54,55] 1 660 1 660 1 660 C5 5N stretch (imines, oximes) [55,57] 1 440 --CH 3 umbrella bending mode [55] 1 390 --C-N stretch (amines, amides) [55] 1 295 --Si-CH 2 wag, C-C-O stretch (carboxylic acids, alcohols, silanols) [55] -1 470-1 260 1 470-1 260 Discrete absorption for as deposited at 1 440, 1 390, 1 295 cm À1 , N-O asymmetric/symmetric stretch (nitro compounds) [58] 1 169 --C-H rocking in CH 3 in CH 3 CH 2 O- [53] 1 080 1 040 1 040 Si-O-Si/Si-O-C symmetric stretch [55,56] 1 100 1 120 1 120 Si-O-Si asymmetric stretch [53][54][55]57] A deeper investigation of the coating chemical changes were performed both for the thermal and plasma post treatment. In the case of plasma, the effect of different parameters as gas feed (i.e., amount of oxygen from 0 to 20%), treatment time and applied power was evaluated ( Table 2).…”

“…Table 5 shows the comparison of the elemental composition (%) together with the elemental ratio of the pd_APS coatings and sol-gel deposited APS coating. [55] The C/Si ratio (Table 5) decrease from 7.2 for the as deposited coating to 5.1 after a thermal post treatment and 2.9 after plasma post treatment. The C/Si ratio for the as deposited coating resembles most to 9 which corresponds to unreacted APS (C 9 H 17 O 3 NSi.).…”

“…The data in literature regarding sol-gel APS conventional films (wet chemistry deposition approach) were used for peak fitting of C1s, O1s, N1s, and Si2p high resolution spectra for plasma deposited films, [55,59] with minor changes due to the formation of new functional groups, as amide and nitro-groups during the plasma process as observed from FTIR spectra. As extensively reported in Table 4, the C1s has been best-fitted in six peak components.…”

Plasma Deposition of an Organophosphorus Coating at Atmospheric Pressure

“…Such grafting of nitrogen species is often observed in AP-DBD coating process when N 2 is used as the main gas process and in absence of oxidizing gas. [44][45][46][47][48] The study of the chemical structure of the coating has been analysed in order to better understand the deposition process. Figure 3 shows the ATR FT-IR spectra of the TEP monomer ( Figure 3a) in comparison with the spectrum of the plasma-polymer thin film (Figure 3b).…”