Direct assembly process

Fig. 5 Schematic showing the four steps of the direct assembly process for building IPMC materials (Reproduced from Akle et al. 2007a, with kind permission from Springer Science and Business Media.)...

Akle BJ, Bennett MD, Leo DJ, Wiles KB, McGrath JE (2007) Direct assembly process a novel fabrication technique for large strain ionic polymer transducers. J Mater Sci 42 7031-7041 Arruda TM, et al (2013) In situ tracking of the nanoscale expansion of porous carbon electrodes. Energy Environ Sci 6 225... 

More recently, a new method of assembling multilayers of PB on surfaces has been described.110 In contrast to the familiar process of self-assembly, which is spontaneous and leads to single monolayers, directed assembly is driven by the experimenter and leads to extended multilayers. In a proof-of-concept experiment, the generation of multilayers of Prussian blue (and the mixed Fein/Run analog ruthenium purple) on gold surfaces by exposing them alternately to positively charged ferric cations and [Fe(CN)6]4- or [Ru(CN)f,]4 anions has been demonstrated.110... 

As a continued effort to prepared hexameric systems based on the self-assembly of directed bw-terpyridine monomers, several interesting in families, e.g. 43, of iron and ruthenium connectivity have appeared <06DMP413, 06DT3518>. But in the assembly process, the creation of a three-step procedure to the novel first nondendritic fractal 44 entitled the "Sierpinski hexagonal gasket" was reported <06MI1782>. 

Figure 11.3. Fluidic flow directed assembly of NWs. (a,b) Schematic (a) and SEM image (b) of parallel NW arrays obtained by passing an NW solution through a channel on a substrate (c.d) Schematic (c) and SEM image (d) of a crossed NW matrix obtained by orthogonally changing the flow direction in a sequential flow alignment process. [Adapted from Ref. 49.]...

Caspar and Klug (1962) made an important distinction between two fundamental types of assembly processes. True self-assembly was conceptualized as a series of reactions relying on the propensity of subunits to condense and form assembled structures strictly as a result of the information encoded in the architecture of the components. On the other hand, template-directed assembly may be considered as a process depending on the presence of a separate template that imparts structural constraints on the pathway for constructing the final assembled structure. True self-assembly is observed, for example, in the formation of many oligomeric proteins. Indeed, Friedman and Beychok (1979) have re-... 

The presence of permanent [Fe2S2] clusters in holo-NifU impeded spectroscopic characterization of transient clusters assembled in a NifS-mediated process. However, unambiguous evidence for NifS-directed assembly of oxidatively and reductively labile [Fe2S2] " clusters on NifU-1 was obtained using the combination of UV-visible absorption and resonance Raman spectroscopies (Yuvaniyama et al. 2000). The anaerobic reaction mixture involved NifU ferric ammonium citrate P-mercaptoethanol l-cysteine NifS in a 50 100 5000 1000 1 ratio. The presence of catalytic amounts of NifS facilitated meaningful UV-visible absorption results and monitoring the time course of cluster assembly. Although ferric ammonium citrate was used for these cluster assembly studies, control experiments... 

The first step of the catalytic process is the hydrogen bond directed assembly and orientation of the reactants. In this example, the azlactone and methanol form a ternary starting complex with the organocatalyst (Fig. 1) [39]. The pseudo-Lewis acidic thiourea forms two bifurcated, nearly symmetric hydrogen bonds (2.147 A, < (0,H,N) = 155.5° and 2.146A, <(0,H,N) = 155.8°) to the carbonyl oxygen atom of the azlactone. 

CHEMICAL KINETICS TEMPLATE CHALLENGE METHOD PROCESSIVITY Template-directed assembly, MICROTUBULE ASSEMBLY Template-directed irreversible polymerization,... 

Nudeobases have pyrimidine and purine (a combination of pyrimidine and imidazole) heterocyclic nuclei which have two ligating nitrogens placed in angular directions. The angular dispositions of pyrimidine, imidazole, and 1,7-purine nitrogens respectively being 120°, 150°, and 90° impart to these bases, heteroatom-induced endocyclic donor ability towards metals which drive self-assembly processes to form macrocyclic systems. The metallacalixarenes formed from nudeobases and various metal salts are discussed with respect to each base. 

The first step of the catalyhc process is the hydrogen bond directed assembly and orientation of the reactants. In this example, the azlactone and methanol form... 

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