Substrate roughness

The important beneficial effects that substrate roughness can bring were firmly established in the late sixties and early seventies, principally as a result of work in two areas. The first was associated with the electroless deposition of metals onto plastics such as ABS and polypropylene. In the process the plastics must be etched in a way which produces pits on a micrometre scale. Such a topography had been shown to be a necessary, but not sufficient condition for adequate adhesion [40]. 

When considering relea.se mechanisms, the physical and chemical heterogeneity of the adhesive/release interface cannot be ignored. At its most basic level, roughness of the release and PSA surface, the stiffness of the PSA and the method in which the PSA and release surface are brought together define the contact area of the interface. The area of contact between the PSA and release material defines not only the area over which chemical interactions are possible, but al.so potential mechanical obstacles to release. In practice, a differential liner for a transfer adhesive can be made to depend in part on the substrate roughness for the differences in release properties [21],... 

S. Garoff, E. B. Sirota, S. K. Sinha, H. B. Stanley. The effects of substrate roughness on ultrathin water films. J Chem Phys 90 7505-7515, 1989. 

In summary, chemical force microscopy appears to be a powerful tool for the study of adhesion on the nanoscale provided that issues such as the detrimental influence of mechanical effects, substrate roughness, packing density, unknown tip radius, and reliance on statistical analysis can somehow be resolved in a consistent and logical way. 

Bouroushian M, Charoud-Got J, Loizos Z, SpyreUis N (2000) A phase modification of CdSe electrodeposits induced by substrate roughness. J Mater Sci Lett 19 2201-2203... 

The nature of the conductance families reported for single alkanedithiol junctions is still under debate. Current interpretations are based on different contact geometries [64, 115, 242], different molecular conformations [64, 244], substrate roughness [245], or the control of tip movement [252],... 

Figure 1.26. Advancing and receding contact angles in the Hg/AI2O3 system measured by the immersion-emersion technique as a function of substrate roughness. Data from work reported in (De...

Fig. 9.4. LPE growth on multicrystalline silicon substrate at INL [23] with equilibrium cooling (left) or yoyo technique (right). Before growth (950° with Sn), substrate roughness is about 2-3 pm. From top to bottom are cross section view, surface view and schematic temperature profile...

Fig. 19 Contact of a soft gel sliding on a rough solid substrate. The substrate roughness I and a are assumed to be much larger than the mesh size of the gel. As the sliding velocity (v) increases, the effective contact area decreases. (Reproduced, with permission, from [66])...

The results show that the friction of a gel on a weak adhesive substrate can be minimized even in the high velocity region, depending on substrate roughness. This result provides some essential ideas for designing a soft gel system with low friction over a wide velocity range, which is important in bioengineering applications where low friction is required, such as in artificial articular joints and artificial hearts. 

The measurement and control of color and gloss parameters is critical because of aesthetic reasons and provides an indirect measure to control process parameters. The impression gloss consists of several appearance phenomena - specular gloss, haze, DOI and surface smoothness. The evaluation of surface smoothness has major influence on the total appearance and is currently only evaluated visually. The presented new measurement technique correlates with the visual assessment of orange peel and objectively measures surface smoothness. The measurement results of the new orange peel instrument (long - and short-term waviness) were related to different process parameters, such as substrate roughness, in an actual case study. 

Table 2.1 Kinetic friction coefficient of polymers (counter part ice (-t), silica glass (++) or steel (elsewhere), p - contact pressure, v - speed of relative lateral motion, - counterface roughness ( substrate roughness), applied normal load in N, RT - room temperature.

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