Hydrophobic/Hydrophilic Patterning

Fig. 20 Multilayer deposition on a hydrophilically/hydrophobically patterned gold substrate. Upper AFM images height (left) and friction force (right) images of patterned methyl- and hydroxyl- alkanethiol self-assembled monolayers. Adsorption of poly(ferrocenylsilane) polyions (5/7, 12 bUayers) occms selectively on the broad methyl-terminated stripes (lower AFM images). Reprinted with permission from [94]. Copyright 2002, American Chemical Society...

Photocatalytic systems based on the plasmon-induced charge separation can be used for oxidation of alcohols, aldehydes, and phenol [8, 13] mineralization of carboxylic acids [14] oxidation of benzene to phenol [15] release of hydrogen from alcohols and ammonia [16] and oxidation and reduction of water (but not water splitting) [17]. The photocatalytic system can also be applied to hydrophilic/hydrophobic patterning based on photocatalytic removal of a hydrophobic thiol adsorbed on metal nanoparticles [18]. 

Hydrophilic/hydrophobic patterning is to prepare two-dimensional patterns consisting of hydrophilic and hydro-phobic regions on a sohd surface. 

Gillmor SD, Thiel AJ, Strother TC, Smith LM, Lagally MG. (2000) Hydrophilic/ hydrophobic patterned surfaces as templates for DNA arrays. Langmuir 16 7223-7228. 

Hydrophobicity is believed to play a major role in organizing the self-assembly of protein molecules. Patterns of hydrophobic versus hydrophilic side chains are very in predicting secondary and tertiary structure simply by virtue of their preferential occurrence on the inside versus outside of various structural features. Those hydrophobicity patterns... 

In the academic setting, inkjet resolution reported for printed organic electronic materials is approximately 20-25 Lxm for untreated substrates and 5 p,m for thermal laser printing. For conductive metallic features, features of 10 Lxm or less have been reported for untreated surfaces. These limits can be further reduced by pretreating the substrate, for example by creating hydrophobic/ hydrophilic dewetting patterns. 

FIGURE 5.5.7 Schematic of stamp-and-spin-cast. Hydrophobic patterns are created by (a) pCP or (b) subtractively removing hydrophobic molecules by UV-ozone irradiation through a shadow mask. An aqueous PANl dispersion is spin-coated on the patterned substrate. PANl features selectively deposit in the hydrophilic regions immediately after the spin-coating. (From K. S. Lee et al., Appl. Phys. Lett., 86, 074102, 2005.)... 

The observed release pattern from both types of microspheres lies in the distribution of the protein inside a microsphere, which is associated with the preparation method. In order to see this, FITC (fluorescein isothiocyanate)-insulin incorporated microspheres were observed under a confocal microscope, as shown in Fig. 7. For Msp A, a homogeneous distribution of fluorescence was observed while Msp B exhibited a rather heterogeneous distribution of FITC-insulin. In addition, Msp B shows significant surface fluorescence. These observations are, hence, consistent with the observed initial burst from Msp B and from the constant insulin release from Msp A over a prolonged period of time. It is reported that the constant release of insulin from triblock copolymer hydrogel may be attributed to the hydrophilic/hydrophobic domain structure of the gel. The incorporation of a significant fraction of insulin in the hydrophobic domain may have made possible... 

Among the molecular species screened by evolution in a Darwinian selection for suitable constituents of first dynamic reality-adaptation and, later, reality-variation and creation patterns, amphiphiles with specific hydrophilic-hydrophobic and order-disorder distributions - sensitized to the chiral message of the electrdweak force -were the preferred survivors of the grand process (Fig. 13) [17, 18, 33]. 

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