Multilayer Adhesion promotion

Kinnane CR, Wark K, Such GK, et al. (2009) Peptide-functionalized, low-biofouling click multilayers for promoting cell adhesion and growth. Small 5 444 48... 

Barrier metals, as opposed to alloys like AuGeNi, are employed in many thin film metallization systems to promote adhesion and prevent interdiffusion. Gold is an excellent conductor, however, it has very poor adhesion to both Si and GaAs. Gold also shortens the device lifetime when it diffuses into an active region of the device. For this reason it is used in multilayered structures such as Ta/Pt/Ta/Au (50), W/Au (50) and Cr/Au (51). SIMS, AES and RBS have all been used effectively in studying metal-metal interdiffusion, to extract diffusion coefficients, and to estimate device lifetimes. 

Chua P-H et al (2008) Surface functionalization of titanium with hyaluronic acid/chitosan polyelectrolyte multilayers and RGD for promoting osteoblast functions and inhibiting bacterial adhesion. Biomaterials 29 1412-1421... 

In addition, allyl methacrylate is often added to a latex formulation as a crosslinking/grafting monomer [52] especially in the case of core-shell latexes. This monomer is often used to promote adhesion between various polymeric layers, especially in multilayered composite latex particles, which are often used as impact modifiers [53]. 

Closer investigation shows that the bond between the first thiol monolayer and the metal surface is destroyed by reoxidation of the iron surface beneath the multilayer film within tens of seconds. Of course, this results in diminished ability of the layers to promote adhesion compared with what would be expected from an intact monolayer. This reoxidation is faster the thinner the multilayer film. For a monolayer film the reoxidation takes about 10s. That is an impressive factor of 10 to 10 slower than for bare iron, achieved by an only 1-nm-thick monolayer film, as can be seen from Figure 7b. 

Chua, P.-H., Neoh, K.-G., Kang, E.-T., Wang, W., 2008. Surface functionalization of titanium with hyaluronic acid/chitosan polyelectrolyte multilayers and RGD for promoting osteoblast fimetions and inhibiting bacterial adhesion. Biomaterials 29, 1412-1421. http //dx. doi.oig/10.1016. biomaterials.2007.12.019. 

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