Influence of residual stress on the adhesion and surface morphology of PECVD-coated polypropylene

Abstract

The properties of plasma-enhanced chemical vapour deposition (PECVD) coatings on polymer materials depend to some extent on the surface and material properties of the substrate. Here, isotactic polypropylene (PP) substrates are coated with silicon oxide (SiOx) films. Plasmas for the deposition of SiOx are energetic and oxidative due to the high amount of oxygen in the gas mixture. Residual stress measurements using single Si cantilever stress sensors showed that these coatings contain high compressive stress. To investigate the influence of the plasma and the coatings, residual stress, silicon organic (SiOCH) coatings with different thicknesses between the PP and the SiOx coating are used as a means to protect the substrate from the oxidative SiOx coating process. Pull-off tests are performed to analyse differences in the adhesion of these coating systems. It could be shown that the adhesion of the PECVD coatings on PP depends on the coatings’ residual stress. In a PP/SiOCH/SiOx-multilayer system the residual stress can be significantly reduced by increasing the thickness of the SiOCH coating, resulting in enhanced adhesion.

Comparison of HMDSO and HMDSN as precursors for high‐barrier plasma‐polymerized multilayer coating systems on polyethylene terephthalate films

“…Further descriptions of duo plasma lines and the utilized reactor are found elsewhere. [ 6,11,12 ] The parameters for coating deposition are given in Table 1.…”

“…The parameters were selected on the basis of the investigations from Jaritz et al, [ 12 ] because it was already shown that by means of the SiO x parameter barrier coatings, and by means of the SiOCH/SiNOCH parameters, less cross‐linked adhesion promoter layers can be produced in this reactor. Furthermore, it was shown in this article that the duty cycle has a direct influence on the degree of cross‐linking and the generation of intrinsic stresses in HMDSO‐based coatings.…”

Atmospheric pressure air plasma treatment to improve the 3D printing of polyoxymethylene

“…One primary method that was used to quantify residual stresses on a polymer flat sheet consists of measuring the curvature of the samples before and after applying the deformation mechanical or thermal load . Once the sample is free of constraints, it restores equilibrium by warping to a shape that resembles somewhat a circular arc …”

Optimizing Crack Onset Strain for Silicon Nitride/Fluoropolymer Nanolaminate Barrier Films

“…For a number of applications of organic electronics, the WVTR and OTR targets for semi-hermetic packaging are 10 –6 g m –2 day –1 and 10 –3 g m –2 day –1 atm –1 , respectively. − The upper-limit requirements of WVTR and OTR for organic electronics are about 6–8 orders of magnitude lower than the corresponding values of commercially available polymer films, whereas improvement by 1–3 orders of magnitude is considered sufficient for applications in food and pharmaceutical packaging . To address this shortcoming, ultrathin barrier films consisting of inorganic brittle materials are deposited on organic substrates as barrier layers to protect the functional layer of the device from oxygen and moisture permeation. − Vacuum deposition methods such as PECVD, ALD, etc., are often used to create the ultrabarrier films, ,− and current ultrathin barrier film technology has reached an effective WVTR on the order of 10 –4 –10 –6 g m –2 day –1 . − …”