Substrate-Independent Layer-by-Layer Assembly by Using Mussel-Adhesive-Inspired Polymers.

Layer-by-layer (LbL) assembly has attracted much attention because of its ability to create multifunctional films on surfaces while maintaining bulk properties. The method relies on sequential adsorption of polymers onto bulk surfaces from solution, giving rise to complex multilayered films. LbL assembly is simple to implement and offers extensive control over film properties and composition during stepwise adsorption of components. Although the vast majority of LbL films are built from polyelectrolytes via electrostatic interaction between layers, more recently LbL films have been made with hydrogen-bonding of polymers, and other building blocks such as inorganic nanoparticles have been used, giving access to even greater control of chemical and physical properties of LbL films. In principle, LbL assembly can be performed on a wide variety of substrates, including noble metals (e.g., Au, Pt), oxides (e.g., quartz, Si, TiO2, mica), and synthetic polymers (e.g., poly(ethylene terephthalate) (PET), poly(methyl methacrylate) (PMMA), polyetherimide). In practice, however, formation of well-ordered LbL layers on many polymeric surfaces has proven challenging, and LbL assembly on hydrophobic polymers such as poly(tetrafluoroethylene) (PTFE), and polyethylene (PE) often requires aggressive ‘‘priming’’ methods such as plasma treatments, oxidative chemical reactions (piranha/persulfonation), or polymeric adsorption. Our goal is to develop a simple, nondestructive and versatile method that enables LbL assembly to be performed on virtually any substrate (noble metals, semiconductors, metal oxides, synthetic polymers, ceramics, and composites) as a useful addition to the LbL toolbox.