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This work introduces photoactivated molecular layer deposition (pMLD) as a route to deposit organic nanoscale polymer films with molecular-level control. Surface-tethered acrylate polymers are obtained through a radical step-growth polymerization where a diene and a diiodo monomer, ethylene glycol dimethacrylate (EGM) and 1,3-diiodopropane (DIP), respectively, are sequentially dosed in the vapor-phase under pulsed UV irradiation. pMLD occurs with a constant growth rate of 3.7 Å/cycle, and both monomers display self-limiting saturation. Films deposited by pMLD exhibit excellent stability in organic solvents. Furthermore, annealing studies with in situ X-ray photoelectron spectroscopy (XPS) reveals thermal stability up to 350 °C in vacuum. The mechanism behind pMLD of EGM and DIP is proposed based on detailed characterization of the polymer films by XPS and Fourier transform infrared spectroscopy, growth modeling, and comparison with control studies of pMLD involving monofunctional precursors. The coupling chemistry of pMLD presented herein provides future possibilities to create apolar linkages in the formation of nanoscale organic films. [ABSTRACT FROM AUTHOR]

Using a one-step electropolymerisation procedure, CO2 absorbing microporous carbazole-functionalised films of iron porphyrins are prepared in a controlled manner. The electrocatalytic reduction of CO2 for these films is investigated to elucidate their efficiency and the origin of their ultimate degradation. [ABSTRACT FROM AUTHOR]

Noveltypes of dual-functional surface-attached polymer brusheswere developed by post-polymerization modification of poly(glycidylmethacrylate) brushes on glassy carbon substrates. Azide and alcoholgroups were initially introduced by epoxide ring-openings of the sidechains. These polymer brushes represent an attractive chemical platformto deliberately introduce other molecular units at specific sites.In this work, ferrocene and nitrobenzene redox units were immobilizedthrough the two groups to create redox polymers. In-depth analysisby infrared reflection–absorption spectroscopy and X-ray photoelectronspectroscopy revealed an almost quantitative conversion of the modificationreactions. The electrochemical activity of the ferrocenyl part ofthis diode-like system was fully expressed with an electron transferrate constant = 1.2 s–1and surface density = 0.19nmol cm–2per nm section of the film, independentof its thickness. In contrast, for the nitrobenzene moieties diffusionof counterions (i.e., tetraalkylammonium) easily becomes the rate-controllingstep, thereby leaving a substantial fraction of them electrochemicallyinactive. [ABSTRACT FROM AUTHOR]

A versatile method based on electrograftingof aryldiazonium saltswas used to introduce covalently attached initiators for atom transferradical polymerization (ATRP) on glassy carbon surfaces. Polymer brushesof ferrocenylmethyl methacrylate were prepared from the surface-attachedinitiators, and these films were thoroughly analyzed using varioustechniques, including X-ray photoelectron spectroscopy (XPS), infraredreflection–absorption spectroscopy (IRRAS), ellipsometry, andelectrochemistry. Of particular interest was the electrochemical characterizationof the electron transfer through the diazonium-based initiator layerto the redox centers in the polymer brush films. It was found thatthe apparent rate constant of electron transfer decreases exponentiallywith the dry-state thickness of this layer. To investigate the electrontransfer in the brushes themselves, scanning electrochemical microscopy(SECM) was applied, thereby allowing the effect from the initiatorlayer to be excluded. The unusual transition feature of the approachcurves recorded suggests that an initial fast charge transfer to theoutermost-situated ferrocenyl groups is followed by a slower electrontransport involving the neighboring redox units. [ABSTRACT FROM AUTHOR]

This work features the controllability of surface-initiated atom transfer radical polymerization (SI-ATRP) of methyl methacrylate, initiated by a multilayered 2-bromoisobutyryl moiety formed via diazonium chemistry. The thickness as a function of polymerization time has been studied by varying different parameters such as the bromine content of the initiator layer, polarity of reaction medium, ligand type (L), and the ratio of activator (Cu(I)) to deactivator (Cu(II)) in order to ascertain the controllability of the SI-ATRP process. The variation of thickness versus surface concentration of bromine shows a gradual transition from mushroom to brush-type conformation of the surface anchored chains in both polar and nonpolar reaction medium. Interestingly, it is revealed that very thick polymer brushes, on the order of 1 μm, can be obtained at high bromine content of the initiator layer in toluene. The initial polymerization rate and the overall final thickness are higher in the case of nonpolar solvent (toluene) compared to polar medium (acetonitrile or N,N-dimethylformamide). The ligand affects the initial rate of polymerization, which correlates with the redox potentials of the pertinent Cu(II)/Cu(I) complexes (L = Me(6)TREN, PMDETA, and BIPY). It is also observed that the ability of polymer brushes to reinitiate depends on the initial thickness and the solvent used for generating it.