Antifriction aminopropyltriethoxysilane films on thermoplastic elastomer substrates using an APPJ system

• Published in: Surface & coatings technology Vol. 310; pp. 239 - 250
• Main Authors: Sainz-García, Elisa, Alba-Elías, Fernando, Múgica-Vidal, Rodolfo, González-Marcos, Ana
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 25.01.2017
• Subjects: Antifriction; Coating; Plasma-polymerization; Silicon oxide; Surface temperature; Silicon oxide; Antifriction; Surface temperature; Coating; Plasma-polymerization
• ISSN: 0257-8972; 1879-3347
• DOI: 10.1016/j.surfcoat.2016.12.079

The study of friction coefficients has long been of great importance in the automotive industry where some areas of the vehicle are subject to slippage. One example is the space between the window channels and the glass. The polymeric materials that are used in these areas, like thermoplastic elastomers (TPE), involve a high degree of friction. So, in order to decrease the friction coefficient of the TPE, companies are using such techniques as flocking. However their high energy consumption, irregular distribution of fibers and poor adhesion are drawbacks. In order to overcome these drawbacks, this work attempts to obtain a SiOx-based thin film over a TPE substrate using aminopropyltriethoxysilane (APTES) with similar or lower friction coefficients and the same durability. Since TPE is heat-sensitive, an atmospheric-pressure plasma jet system (APPJ) with a dielectric barrier discharge (DBD) was used in this study. The influence of the plasma power and number of passes was characterized by Profilometry, Atomic Force Microscopy (AFM), Scanning Electron Microscopy (SEM), Attenuated Total Reflectance-Fourier Transform Infrared (ATR-FTIR) Spectroscopy, X-Ray Photoelectron Spectroscopy (XPS), Water Contact Angle (WCA) measurements and friction coefficient. The average surface temperature of the samples and the coating thickness seem to be the key variables in determining the friction behavior. Successful samples (those that have a lower friction coefficient than those of the current industrial solutions - flocked seals and polyamide tap) were coated at an average surface temperature of <92°C and thicknesses of the coatings were >1000nm. Sample coated in six passes and the lowest power (350W) proved to have the best friction performance. This sample has a friction coefficient that is 46% lower than that of the flocked seals. The results of this research permit one to conclude that a promising antifriction technology using APPJ with a DBD could be an alternative to the current industrial solutions. [Display omitted] •SiOx thin films on TPE by APPJ using APTES varying plasma power and residence time•Friction and wettability have been improved over flocked seals and polyamide tape.•Residual thermal stress explain anti-friction performance.•The best sample (S6/350) had a friction that was 46% lower than flock friction.•Successful coating: process temperature below 92°C and thickness >1μm