Preparation of Gradient Surfaces

A surface whose physicochemical properties gradually change as a function of the position is called a gradient surface. While the gradient surface has potential applications as a substrate for combinatorial studies [29-31], the gradient of surface wetting is of particular interest because spontaneous motions of a droplet are induced on the surface [32]. 

Catalysis ferrocene [13], Ni-azamacrocyclic complex [14], metal-porphyrin [15] 

Optical second harmonic generation ferrocenyl-nitrophenyl elhylene [16] 

Wetting control carboxyl group [6], hydroxyl group [6], sulfonic acid [6], methyl group [6] 

Bonding carboxyl group [24], amine [25], phosphonate [26], ihiol [27] 

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An additive-free PE sheets, 250-300 pm thick (Hanyang Chemical Co., Korea), were cut into 5.0 X 7.0 cm pieces and ultrasonically cleaned twice in ethanol for 30 min. The PE sheets were treated with a radio-frequency corona discharge apparatus made by our laboratory for the preparation of gradient surfaces (Fig. 1). The PE sheet was placed on the sample bed and dry air... 

The use of a chemical reaction on a polymer surface is an important method for preparing a gradient surface. The key advantage of this technique is that the surface can be modified to have very distinctive properties through the choice of different functional compounds, since these are bound covalently to the solid surface under controlled conditions [309, 314, 315]. 

Fig. 3 Preparation of surface-grafted polymer brush composition gradient. Reprinted with fter-mission from [15]. (Copyright 2006 Wiley-VCH Verlag GmbH Co)...

Morgenthaler S, Lee S, Zurcher S, Spencer ND (2003) A simple, reproducible approach to the preparation of surface-chemical gradients. Langmuir 19 10459-10462... 

Fig. 26 Schematic diagram of the preparation of a gradient surface varying unidirection-ally in thickness of the photograft-copolymerized layer by using the combination of two types of photomasks and the X-Y step motor-controlled stage...

The pulsed field gradient NMR technique can be readily used for the determination of the water droplet size distribution in W/O emulsions or the oil droplet size distributions in O/W emulsions. Important advantages are the non-invasive nature, the ease of sample preparation, and the feet that pulsed field gradient NMR measures the droplet size distribution of the bulk in contrast with microscopic methods which estimate the size distribution of the surface. Both the proposed matrix method and the iterative curve fitting procedure can be successfully applied in a factory environment. The method can be implemented on a high as well as on a low resolution NMR spectrometer. 

A series of articles is devoted to the preparation of Pc complexes from metal alloys ([21a] and references cited therein). The most important advantage of the alloys use is an easier reaction between phthalonitrile and the alloy s component(s), due to a concentration gradient of metal particles on the alloy surface. As a consequence of such an interaction, it is possible to obtain polynuclear phthalocyanines and separate the alloy [21a]. This relatively new and intriguing field in Pc research should undoubtedly be taken into account. Another nonstandard technique for metal phthalocyanine production is the use of microwave irradiation under solvent-free conditions (for more details see Sec. 3.5). In particular, this method was used for obtaining phthalocyanine derivatives of Ru, Rh, Pt, and Pt [21b], Zn, Mg, Co, and Cu [21c], or Si [21d]. 

The method contains three stages including first establishing a cell line followed by test chemical exposure and finally evaluated for expression of cell surface markers. To establish a cell line, human leukocyte preparations are attained from a plasma distributor. The leukocyte preparations as described by Ryan et al. (2004), are diluted with an equal part of complete medium (RPMI 1640 containing 1 x L-glutamine, 1 x penicillin-streptomycin-neomycin antibiotic mixture), 30 p,2-mercaptoethanol and 10 % heat inactivated fetal bovine serum. The diluted preparation is layered onto a Ficoll-Paque gradient to... 

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