Surface Grafting Modification Of Materials Based On Dopamine Derivatives

Control of surface properties is of great importance in materials science, chemistry and biotechnology. Surface modification is necessary as most materials cannot meet the actual requirements. Dopamine and its derivatives can adhere to almost any surface under mild conditions, which promote the development of new surface modification methods. This paper provides new methods for Surface grafting modification of materials based on dopamine derivatives. Our research has three main aspects:1. We provided a facile and versatile method for surface modification combining the advantages of dopamine and conventional radical polymerization(with wide range of monomers). First, a dopamine derivative, dopamine methacrylamide(DAMA, a molecule with adhesive properties that mimic those of mussels) was subjected to oxidative polymerization in a basic aqueous medium to coat the substrate. Carbon-carbon double bonds were thus formed on the surface and could subsequently be copolymerized with 1-Vinyl-2-pyrrolidinone(NVP) and 2-(Dimethylamino)ethyl methacrylate(DMAEMA) by radical polymerization. Both DAMA deposition and polymer grafting were unambiguously confirmed by static water contact angle, fourier transform infrared reflectance(FTIR) spectroscopy and X-ray photoelectron spectroscopy(XPS) measurements. Protein adsorption assays showed that PVP-modified PVC and SPR sensor chips have good protein-resistant properties, with 70% and 85% Fg adsorption decreased respectively. Antibacterial activity test performed with quaternized PDMAEMA-modified PVC showed substantial antimicrobial capacity against Escherichia coli(E. coli) as compared to the unmodified substrates.2. A dopamine-based iniferter agent was designed for the functionalization of titanium surfaces. First, we synthesized a new iniferter agent(4-((3,4-dihydroxyphenethyl) carbamoyl) benzyl diethylcarbamodithioate, DMBD) incorporating a dopamine moiety, which was used to mediate iniferter polymerizations of common monomers such as N-Isopropylacrylamide(NIPAAm), DMAEMA and NVP. Subsequently these polymers were immobilized on titanium surfaces through chelation interaction between catechol and titanium. The resulting films were characterized by contact angle and XPS investigations.3. We demonstrate the use of DMBD for surface-initiated photoiniferter-mediated polymerization(SI-PIMP) from Au surfaces to create polymer coatings. The iniferter agent DMBD was firstly immobilized on Au surfaces by simple dip-coating. After that, SI-PIMP was performed through the adsorbed iniferter agent to polymerize DMAEMA and N-[3-(Dimethylamino)propyl]methacrylamide(DMAPMA). FTIR analysis confirmed the successful grafting of iniferter agent and polymer. In addition, the results of ellipsometry test indicated the thickness of polymer coatings was well controlled.