Antimicrobial surfaces of viologen-quaternized poly((2-dimethyl amino)ethyl methacrylate)-Si(100) hybrids from surface-initiated atom transfer radical polymerization

To improve the antimicrobial ability of silicon-based bioelectronics and to tailor the silicon surfaces for inhibiting biofilm formation, well-defined functional polymer-Si(100) hybrids, consisting of nearly monodispersed poly((2-dimethylamino)ethyl methacrylate) (P(DMAEMA)) covalently tethered on the silicon surface and functionalized by viologen moieties, were prepared. P(DMAEMA)-Si hybrids were prepared via surface-initiated atom transfer radical polymerization (ATRP) of (2-dimethylamino)ethyl methacrylate (DMAEMA) on the hydrogen-terminated Si(100) surfaces (Si−H surfaces). The tertiary amino groups of the covalently immobilized (Si−C bonded) P(DMAEMA) brushes on the silicon substrates were quaternized by an alkyl halide to produce a high concentration of quaternary ammonium groups with biocidal functionality. Alternatively, covalent coupling of viologen moieties to the tertiary amino groups of P(DMAEMA) brushes produced the quaternized P(DMAEMA)-Si(100) hybrids with substantially enhanced antimicrobial capability, as well as capability to effectively inhibit biofilm formation. Thus, the viologen-quaternized P(DMAEMA)-Si(100) hybrids possess good antibacterial surface properties and are potentially useful to the silicon-based bioelectronics to ensure their efficiency, durability and reliability.