Patterned surface

Dry etching is a commonly used teclmique for creating highly anisotropic, patterned surfaces. The interaction of gas phase etchants with surfaces is of fundamental interest to understanding such phenomena as undercutting and the dependence of etch rate on surface structure. Many surface science studies aim to understand these interactions at an atomic level, and the next section will explore what is known about the etching of silicon surfaces. 

Warping, difficulty of moulding to close tolerances and wavy or fibre-patterned surfaces or faults arising from the high shrinkage during cure. 

Anchor Pattern (Surface Profile)—the shape and amplitude of the profile of blast-cleaned or grooved steel, which influences the bond between metallic or paint films and the substrate. 

H. Kallabis, D. E. Wolf. Growth of patterned surfaces. Phys Rev Lett 79 4854, 1997. 

Felix et al. [44] recently measured the film thickness profiles on a patterned surface with artificially manufactured asperi-... 

The low nonspecificity of PEG layers also was used to eliminate biomolecule binding to certain areas of an array. Kidambi et al. (2004) patterned an mPEG-carboxylate molecule onto polyelectrolyte multilayers to mask portions of the surface. The extremely low binding character of PEG provides advantages for creating patterned surfaces that other modifiers using aliphatic alkyl linkers do not provide. 

In the mid Atlantic ocean observed concentrations at A03 and A04 decrease gradually with depth, whereas A05 concentrations show an increase until 500 m and a decrease below. Modeled profiles show a similar pattern. Surface concentrations of model results are much lower than the observed ones. In addition to this the fact that profiles of all mid Atlantic sampling location are identical can be explained by missing discharge into the mid Atlantic ocean in the emissions scenario. Emissions from American fluoropolymer productions sites are released into the Atlantic Ocean solely at the mouth of St. Lawrence River. Discharge of PFOA into for example the Gulf of Mexico is not considered. 

Figure 11.4. Fluidic flow-directed assembly of NWs. (a,b) Schematic (a) and SEM image (b) of regular NW arrays obtained by flowing NW solution over a chemically patterned surface. (c,d) Parallel and crossed NW device arrays obtained with fluidic flow assembly. [Adapted from Refs. 44 and 49.]...

The formation of bottom-up block copolymer patterns within or on top-down substrate patterns is the basis for so-called templated self-assembly processes, in which long-range order and orientation of microdomain patterns can be imposed by a template or guide . These top-down templates can take a variety of forms including periodic thickness profiles and chemically patterned surfaces. 

By modifying the surface/interface energies in a periodic manner, chemically patterned surfaces have also been widely used to control the orientation of nanostructures over large areas (Fig. 6). Theoretical [138-145] and experimental [73-76,88,89,146] results have indicated that with the appropriate surface grating and boundary conditions, lateral control over nanostructures propagates microns away from the surface (deep into the film), thus providing true 3D control of the self-assembly process. Russell and coworkers [73,74]... 

Laterally-defined heterogeneous polymer surfaces can be created by using a homogeneous layer of an azo initiator. UV irradiation through a mask in the presence of monomer leads to the locally confined photopolymerization [234]. A second polymerization using the remaining initiators results in patterned surfaces composed of two types of polymer brushes [238]. However, the lateral resolution of obtainable patterns is hmited by the irradiation used and type of mask (in this case polymer brush patterns of 260 tm spaced by -40 pm were formed). 

Finally, hyperbranched polymer layers by surface-initiated step polymerization was intensively studied mainly by Bergbreiter et al. and Crooks et al. Patterned surfaces were prepared on the micrometer scale and a variety of functional groups introduced interesting optical, electrochemical, biological, and mechanical properties into the films. For a recent review on surface-initiated step polymerization resulting in branched polymer layers see [352]. 

Besides homogeneous and uniform SAMs or polymer brushes, systems of tailored heterogeneity such as mixed monolayers of two or more compounds, gradients, block copolymer brushes etc. are now under investigation. Especially, the development of patterned surfaces offers the exciting possibility to perform multiple parallel experiments on a single substrate or cascade reactions. 

Self-Assembly of Polymers and Nanoparticles on Patterned Surfaces... 

Some evidence such as burn char patterns, surface fractures, or volatile chemicals spills can degrade as a result of weather conditions (rain, wind, or sunlight)... 

Fig. 23 Site-selective attachment of NAs onto chemically patterned surfaces...

Various fabrication schemes have emerged using this approach. A common one is the site-selective photochemical etching of an organosilane-modified surface by irradiation through a mask [86]. This results in a chemically patterned surface with active sites, where modified ONDs can be attached, surrounded by bare (irradiated) regions. 

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