Surface initiators

Qualitatively, it is observed that the mercury surface initially is positively charged, and on reducing this charge by means of an applied potential, it is found that the height of the mercury column and hence Ae interfacial tension... 

The mathematical model chosen for this analysis is that of a cylinder rotating about its axis (Fig. 2). Suitable end caps are assumed. The Hquid phase is introduced continuously at one end so that its angular velocity is identical everywhere with that of the cylinder. The dow is assumed to be uniform in the axial direction, forming a layer bound outwardly by the cylinder and inwardly by a free air—Hquid surface. Initially the continuous Hquid phase contains uniformly distributed spherical particles of a given size. The concentration of these particles is sufftcientiy low that thein interaction during sedimentation is neglected. 

The Clemmensen reduction can be formulated to proceed by a sequence of one-electron and proton transfer reactions. It is a heterogenous reaction, taking place at the zinc surface. Initially an electron is transferred from zinc to the carbonyl group of ketone 1, leading to a radical species 3, which is presumed to react further to a zinc-carbenoid species 4 ... 

Wang J, Gibson MI, Barbey R, Xiao SJ, Klok HA (2009) Nonfouling polypeptide brushes via surface-initiated polymerization of N-epsilon-oligo(ethylene glycol)succinate-L-lysine N-carboxyanhydride. Macromol Rapid Commun 30 845-850... 

The chain architecture and chemical structure could be modified by SCVCP leading to a facile, one-pot synthesis of surface-grafted branched polymers. The copolymerization gave an intermediate surface topography and film thickness between the polymer protrusions obtained from SCVP of an AB inimer and the polymer brushes obtained by ATRP of a conventional monomer. The difference in the Br content at the surface between hyperbranched, branched, and linear polymers was confirmed by XPS, suggesting the feasibility to control the surface chemical functionality. The principal result of the works is a demonstration of utility of the surface-initiated SCVP via ATRP to prepare surface-grafted hyperbranched and branched polymers with characteristic architecture and topography. 

Tsujii, Y, Ohno, K., Yamamoto, S., Goto, A. and Fukuda, T. (2006) Structure and properties of high-density polymer brushes prepared by surface-initiated living radical polymerization. Adv. Polym. Sci., 197, 1-45. 

The first report of the SERS spectrum of a species adsorbed at the electrode/ electrolyte interface was by Fleischman et al (1974) and concerned pyridine on silver. The Raman spectrum of the adsorbed pyridine was only observed after repeated oxidation/reduction cycles of the silver electrode, which resulted in a roughened surface. Initially, it was thought that the 106-fold enhancement in emission intensity arose as a result of the substantially increased surface area of the Ag and thus depended simply on the amount of adsorbate. However, Jeanmarie and Van Duync (1977) and Albrecht and Creighton (1977), independently reported that only a single oxidation/reduction cycle was required to produce an intense Raman spectrum and calculations showed that the increase in surface area could not possibly be sufficient to give the observed enhancement. 

Recently, Kong et al. [159] functionalized MWNT with polyacrylic acid (PAA) and poly(sodium 4-styrenesulfonate) (PSS) by surface-initiating ATRP (atom transfer radical polymerization) following the Schemes 1 and 2 ... 

In order to recognize the pattern of reactivity of alcohols on modified nickel surfaces, it is essential to know the reaction pathways exhibited by less reactive surfaces. Initially the dehydrogenation of CH3OH was studied on copper (4 ) and silver (5 ) single crystal surfaces. On Cu(110), following the preadsorption of submonolayer quantities of atomic oxygen, methanol reacted via the following sequence (4,6) ... 

Surface-Initiated Polymerization I Volume Editor Jordan, R. 

Wang, D., et al., Graphene functionalized with azo polymer brushes Surface-initiated polymerization andphotoresponsiveproperties. Advanced Materials, 2011. 23(9) p. 1122-1125. 

Also evident in Fig. 64B are small light-colored clusters close to 1/2 nm in size. At present it appears that these clusters are extra CdSe formed because too much Se was present on the surface initially (Fig. 64A). As mentioned above, the Se coverage prior to Cd deposition appeared close to 0.6 ML—significantly greater than the 0.44 needed for the structure diagrammed in Fig. 63B. Studies have shown that Cd will react nearly stoichiometrically with up to several monolayers of Se [107]. These results are consistent with the discussions of CdTe formation in Fig. 41C, where a second layer begins to form and results in island on the surface. 

Fig. 9.19 Preparation of polymer brushes on solid surfaces by a) chemical grafting of end-functionalized linear polymers or selective adsorption of asymmetric block copolymers and b) by surface-initiated polymerization (SIP) using initiator functions on the solid surface. The depicted SAM bearing to-functionalities...

In this method, a reactive group on the surface initiates the polymerization, and the propagating polymer chain grows from the surface (Fig. 9.19b). In principle, it can be employed with all polymerization types, and a number of papers have reported high amounts of immobihzed polymer using surface-initiated polymerization with various initiator/monomer systems. If controlled or Hving polymerization techniques are used, block copolymer or end-functionahzed polymer brush systems can be prepared in consecutive reaction steps (Fig. 9.19c). 

Tab. 9.2 Specific surface modifications and SAM systems of particles or planar substrates for the surface-initiated free radical polymerization of vinyl monomers. 

Surface-initiated Poiymerization Using Free Radical Polymerization... 

Surface-initiated Polymerization Using Living Ionic Polymerization... 

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