Surface Functionalization of Silicone Rubber for Permanent Adhesion Improvement

Abstract

The surface properties of poly(dimethyl siloxane) (PDMS) layers screen printed onto silicon wafers were studied after oxygen and ammonia plasma treatments and subsequent grafting of poly(ethylene -alt-maleic anhydride) (PEMA) using X-ray photoelectron spectroscopy (XPS), roughness analysis, and contact angle and electrokinetic measurements. In the case of oxygen-plasma-treated PDMS, a hydrophilic, brittle, silica-like surface layer containing reactive silanol groups was obtained. These surfaces indicate a strong tendency for "hydrophobic recovery" due to the surface segregation of low-molecular-weight PDMS species. The ammonia plasma treatment of PDMS resulted in the generation of amino-functional surface groups and the formation of a weak boundary layer that could be washed off by polar liquids. To avoid the loss of the plasma modification effect and to achieve stabilization of the mechanically instable, functionalized PDMS top layer, PEMA was subsequently grafted directly or after using gamma-APS as a coupling agent on the plasma-activated PDMS surfaces. In this way, long-time stable surface functionalization of PDMS was obtained. The reactivity of the PEMA-coated PDMS surface caused by the availability of anhydride groups could be controlled by the number of amino functional surface groups of the PDMS surface necessary for the covalent binding of PEMA. The higher the number of amino functional surface groups available for the grafting-to procedure, the lower the hydrophilicity and hence the lower the reactivity of the PEMA-coated PDMS surface. Additionally, pull-off tests were applied to estimate the effect of surface modification on the adhesion between the silicone rubber and an epoxy resin.

Synchrotron-radiation-stimulated etching of polydimethylsiloxane using XeF2as a reaction gas

“…7(a), 7(b) and 7(c), respectively. Before etching, two features were observed in the C 1s region; one, at 284.7 eV, is assigned to C of PDMS (Roth et al, 2008) and another, at 287.7 eV, to the carbon contamination, as shown in the spectrum of the gold thin film (see Fig. 7c).…”

“…After removal of the etching mask, each etched hole was found to have a size of 35 mm square at the bottom and 45 mm square at the top. The difference between the mask pattern and the etched pattern was explained by diffraction effects and an uncontrollable gap between the mask and the PDMS sample surface (Roth et al, 2008). In particular, the side etching ($ 20 mm depth) observed at the pattern edge (top of the hole) may be due to the secondary electrons, scattered photons and fluoride ions or metastable atoms entering the gap between the mesh and the PDMS surface.…”

Factors Affecting the Bond Strength between Denture Basis and the Soft Relining Materials - A Review

“…In most of the cases it contains an organic dissolving agent and a monomer, which dissolves the acrylic base and reacts simultaneously with both materials [38]. The organic solvent affects the depth of penetration of the monomer and the reactivity of the added liner as well [39,40]. MA is a reactive monomer, containing unsaturated double bond and acid anhydride groups.…”

Farklı yumuşak astar materyallerinin Candida albicans biyofilm formasyonu açısından değerlendirilmesi

“…3,9,10 Mükemmel fleksibilite, sağlamlık ve yüksek termal ve oksidatif stabiliteleri gibi istenen özelliklere karşın, PMMA ile güçlü adezyon sağla-yabilen reaktif yüzey gruplarına sahip değildir. 11 Ayrıca, göreceli olarak yüksek miktarda düşük moleküler ağırlıklı bileşenleri de PDMS'nin protez kaide rezinine adezyonunu etkiler. Bu zayıf ara yüz bağlantısı bakteriyel çoğalma, plak ve diş taşı oluşumu gibi bazı sorunları tetikler.…”